As you read them, maybe see if you can come up with some name possibilities? The project really needs a name (I have gone all mafia about it and taken to calling it "our thing," which probably won't work), which will make it easier to talk about and enable us to get started on cool things like logo contests, to keep people excited and involved.
I'm also going to refer to LJ plus its clone sites (JF, GJ, IG, Scribblit) as "LJC."
Thing we like about LJ: Our friends lists
Ways to make it better: Stop calling it our "friends list." Ability to click the "also friend of" link so you can see who's reading you (I think we should totally call this function "who watches the watchers?" or maybe just "quis custodiet"); makes it easier to decide if you want to add them to your reading list. Some tech stolen from RSS readers so you can close a post when you're done with it; makes you less likely to miss things and easy to come back to posts later. No friends limit.
Thoughts: The nomenclature has really got to change, and that's not going to be difficult to do. I gather the reasons for f-list limits has something to do with server and bandwidth resources. Possibility of setting the limit as high as we reasonably can and allowing users to purchase the ability to increase that limit? I would like to have no limits at all, but that's going to depend on the sort of back-end we have.
Migration Madness: Will need a way to read journals from LJC on reading list. dizzycadence is working on a way to do this w/ authentication so you can also read locked posts. (Assuming they've got you friended.) More info here. Also, implement clone-based username linking: < lj user= , < jf user= , < gj user= , < ij user= , < sc user= .
Thing we like about LJ: Layouts
Ways to make it better: Support for external stylesheets. Make it easier to customize fannish layouts without having to learn arcane S2 rules.
Thoughts: I think external stylesheets are a must-have. And while we're talking markup, validity & accessibility will be paramount, so the site will be browsable by non-standard methods (voice browsers, iPhones, Lynx, whatever. I actually do a surprising amount of text-based browsing these days).
One step further: Tag-based filters + linked stylesheets/custom layouts = a page of Pirates posts with a nice Pirates layout. One click and you're looking at a page of PoT posts with Tezuka in the background.
Thing we like about LJ: Icons
Ways to make it better: More of them. Mass uploading. Saved keywords. Longer keywords. Multiple keywords. Maybe tags instead of keywords (so, "show me all of so-and-so's Naruto icons" will be a possibility)? Larger icon (byte) size?
Thing we like about LJ: Image hosting
Ways to make it better: Allow comments to scrapbook images. Add vid hosting.
Thoughts: I feel like scrapbook needs to be seriously re-imagined. I have not done said re-imagining. I think people use scrapbook for a few different things: artists to host their artwork, picspammers to host this week's pictures of Johnny Depp, icon-makers to store icons, others to put up misc. pics of their cat or store the art they need for their layouts. Maybe do something like split this functionality in two: galleries, with thumbnails and tags and the ability to comment on pictures; and something that works a lot more like an ftp server, so you just have storage space and you can upload the 150 icons you just made and call them whatever you want to call them. Maybe? Also, if storage were more FTP-like, you could put up things that weren't necessarily images. Still thinking about this piece of it.
Thing we like about LJ: Comments. Comment threading. Comment notifications.
Ways to make it better: Editable comments. Formatting options (RTF? Wiki formatting?). Easy previewing. "Unfold all."
Thoughts: Apparently the "unfold all" thing comes up in suggestions, and it's always determined that it's too much of a resources hog. Would it help to do it without icons? What about making it a feature you can purchase? Editable comments (with system-added datestamp, like in forums?) and formatting options FTW.
Thing we like about LJ: Tags
Ways to make it better: Ability to subscribe to certain tags of certain users. Ability to not subscribe to certain tags of certain users. Ability to search the site by multiple tags. Tag browsing. Tags, tags, tags.
Thoughts: I think we might also want to tag our actual journals and communities, to make searching/browsing easier. I think this would work a bit like interests, except better; it'd allow us to easily look for, say, users and communities with a lot of Battlestar Galactica femmeslash.
Thing we like about LJ: Memories
Ways to make it better: Nested categories for better/easier organization. Tag memories. Move them around, edit them, delete them without it being a tremendous pain-in-the-ass. Add notes or comments to the links you add to your memories. Add outside links to your memories.
Migration Madness: There would ideally be a way to transfer memories to the new service. I suspect it may be possible to hack antennapedia's lj migrate script to do this. Will maybe work on that now, because I'm kind of ansty to get coding. *grin*
One step further: People talking about the functionality they'd like to see in the memories section started to sound a lot like people talking about del.icio.us. Adding del.icio.us-like bookmarking to the site? Made of win.
Thing we like about LJ: Communities
Ways to make it better: Easily back up entire community, comments and all. Better moderator functionality, like the ability to change the security on every community post at once.
Thoughts: One thing that was brought up was, put some measure in place for when comm mods disappear. I'm not sure there's a way to do that with code, but maybe there could be some kind of policy in place like, if no one hears from the mod in X days, comm members can elect a new one and the site admins can make it happen.
One step further: I like the idea of community types. When you go to create a community, obviously you have to option to make it be whatever you want. But maybe newsletters are a special type of community, where you set up a post template and enable the "I edit a newsletter" feature, and then as you're browsing, each post has an "add to newsletter" button by the "add to memories" button and all the other little buttons. Or you make a fanworks community and have the option to add challenges to a Master Fandom Calendar (more on the MFC later).
Thing we like about LJ: Filters
Under consideration: Levels of "public," such as locking entries to logged-in users only. Ability to label posts NSFW combined with a default SFW filter (by default I mean it's always available if you want it, not that you're forced into using it). Ability to lock posts to all members over  (actual age TBD) or all members AND guests over . Only okay if easy and largely unobtrusive cookie-based "yes, I'm of age" guest-pass thing is possible (which it should be). No, it will not keep the kids out. Yes, it will cover our asses.
Thing we do not like about LJ: The amazing changing unchanging TOS
Ways to make it better: Be clear. Be detailed. Be responsive. Have some balls.
Statement: Not even under debate. This will happen.
Thing we do not like about LJ: Search functionality is well-nigh useless
Ways to make it better: Search by tags -- more than one at a time. Ability to narrow results. Search by fandom.
Thoughts: I'm probably going to put together a mockup of what I think the search page is going to look like, and then solicit input. This, I feel, is really important functionality and it's going to help to have an idea of what we want early on, because it's going to be a big driver of the data model.
One step further: While I absolutely think that users should be able to opt out of having their individual journals searchable (much like what LJC does now with appending the norobots stuff to headers), I think it would be AWESOME to be able to have a little search thing on posts that lets you search through (collapsed) comments to a given post.
Thing we can't decide if we like about LJ: Paid accounts
Likely course: Free accounts + option to buy highly modular add-ons. No generic "paid account" as such, but allow users to purchase the add-ons they want and will use. Possibly offer packages for the super-lazy.
More info: Because this is going to be a non-profit venture, the only purpose of charging for add-ons is allowing us to afford the resources to provide them. I'd like as much of this stuff as possible to be free, but right now, I have absolutely no way of knowing what we will and will not be able to provide. It's also going to vary depending on what users want. So, the very tentative "maybe it will cost extra" list: voice posts, a gazillion icons, pages, vid hosting, killfilters, unfold-all, more layouts, SMS capability, actual server space (http://user.awesomename.com/site/)
Thing we can't decide if we like about LJ: The nav bar
Thoughts: Some people like it, some people hate it. At the very least, if it's going to be an option, it should be customizable (and maybe hideable?). I kind of like the idea of a nav bar made of widgets.
Thing LJ has never heard of: Master Fandom Calendar
How it works: You create a community. The system says, "hey, is this community going to have challenges?" If so, you can add them to the Master Fandom Calendar, which users can go check out and view by fandom. Anyone can add new events, but only event creators or their (designated) proxies can edit or delete them.
Why? It would be hugely cool? It would help foster a sense of community? I know challenge-listing communities pop up all the time, asking people to show up and announce that they're running such-and-such type of challenge. Everyone thinks they're a good idea, and they last for like two weeks, and then people stop posting. I think making "add a challenge" an automated process that the system takes care of would help a lot.
Thing LJ has never heard of: Master/slave accounts
How it works: You sign up with an e-mail address and set up your main account. You can then set up other accounts (for RL stuff, RPGs, whatever) and link them to that same e-mail address. All features of all accounts are accessible from the master account.
Other thoughts: I love this idea, but I'm torn about implementation. Should Master accounts get unlimited slaves? Or they get X number of slaves and can buy more? I like the idea of purchasing add-ons and then allowing users to split them up between accounts as they see fit. So, buy 100 additional icons, and give 10 of them to your RL account and 35 to some RPG account and the rest to your fannish account. Etc.
Thing LJ has never heard of: RPG consoles
How they work: Easy way for mods to see what's going on in their games -- maybe a listing more like a forum so they could see where the most recent activity is. What else? I'm not an RPer, so I don't know.
Thing LJ has never heard of: Post templates
How they work:The site has default templates for different types of post (fic, art, regular journal entry, icons, whatever). Users won't have to use them if they don't want to, but it'd be shiny if they did, because then we could use those fields as metadata to search against. Fields and field values editable by user.
Think LJ has never heard of: Account types
How they work: Much of this functionality is fen-specific, but I also want this site to be a place where non-fen can feel at home. I think it'd be kind of nice to say, when you are creating your account, "no, I don't want all the fannish bells and whistles," and then you won't be bothered with quite so many fannish options. Obviously, you should be able to change that at any time, and activate said bells and whistles.
Whew. Okay. That's a lot. But see what I mean about how awesome it will be if we can even do half this stuff?
So. Anything I missed? Other thoughts?