For just point 3:
I think one of the major obstacles might not be as much (perceived) technical problems as it's lack of perceived gain. If you ask a random viewer, chance is that they can't see much if any improvement from a CFR XviD encode to a CFR x264 encode, most people simply don't see a difference or don't care about it. "Why bother if I don't gain anything?"
Div3 on the other hand had all kinds of odd problems that were easy to spot and were very clearly worse quality than what XviD delivers/delivered, and the XviD files even were smaller to deliver that better quality. So of course the viewers would switch there.
Now what very obvious problems does H.264 in MP4/MKV solve that XviD in AVI doesn't already provide a solution to? Nothing anyone would really care about, current Xvid/AVI releases are already as watchable as things need to be, you need to be an encoder to really appreciate the gains.
So a quick shot at point 3 might be in order, how about beginning to offer
even smaller H.264 encodes than current XviD encodes while avoiding a quality drop? I believe that (at least for SD resolutions) that's a much more viable option than telling about all the invisible gains of same-sized H.264 encodes.
And while at the size issue, I once again beg to drop those N-eps-per-CD/DVD file sizes. I believe most if not all of the people who archive anime have switched to DVD's now, so it'll generally not be as much (potentially) wasted space per disc when the file sizes fall. Of course there's still the "full anime on one or two discs" issue, but really... does it matter that much? It's nowhere near as bad as with CD's, with CD's you'd have to change disc all the time, with DVD's it's at most two disc changes for average series anyway.
Uh, maybe that was a bit off-topic, mods feel free to split it away
