Grid Design: I like old-school sprawl grids, so my preference is opposite here. I think you can split the difference somewhat, however, by: instead of building a traditional grid grid, and a temproom nexus, build a very small grid where the 'grid rooms' describe a very large area, and allow people to spawn temprooms from there that would be locations in that area. I considered doing this for a multi-planet grid: 'planet' would have been a single grid room, and people could spawn locations from there as needed. Now, granted, it's a little more relevant to know what planet someone is on than what major area they're in, this can be relevant if some major staff-led event goes down. Having a few built and stable-ish sphere locs as needed can also be a benefit. You can basically split the difference here, is what I'm saying: strip the actual 'grid' down even further, then temp it from there. (Strip, burbs, desert, mountains, whatever, done, for example.)
Social RP: I think it has value and gives context to things. It's good for downtime. I don't think you need to treat every birthday party as a major plot (because that is silly), but you also do not want to bash the shit out of it to the extent that people feel ashamed to be seen RPing something casual or social ever, or like the game view of that RP is wrongfun. That's a quick recipe for people doing more nothing in their downtime than many already do.
Homework: I don't consider a minor background a big deal. I think a general character overview that mentions anything extraordinary is maybe better than the standard 'tell me more about your mother... ' that always sounds like a first appointment with a novice shrink. Depending on how much you're cool with having public, I may be able to help with a log form, and may be able to do some other submission stuff like that as well. People are iffy about that, but some stuff is possible. I was able to figure out how to get a log submission form set up that'd calculate XP per player based on the metrics I was using, which also included some of the CoD stuff like breaking points and aspirations filled in scene. It makes it more time and effort to submit the log, but it did all the calculations for you and could spit out a script for staff to just paste into the game after looking it over with a total for the ST and an individualized breakdown per player. If you're sticking with just the basics of CoD and maybe some kind of <time period> or theme incentive, that can be reproduced pretty easily if it sounds like it would help out on the homework front.
Making things matter: Mrr. I'll get back to you on this one. My ideas in this vein are weird and trended toward a different sort of game model lately so I'd have to get back to you about it.