Great suggestions. I've been a proponent of the Wiki, too, although it really hasn't come off the ground yet. First, some thoughts on your points:
1. The organization of the AA area parallels that of the rest of the FlyerTalk Wiki, and so for the sake of consistency, it might be best to leave it as is. I agree that there is some overlap, but within certain bounds I think it would be possible to keep the current arrangement. Scanning the articles we have right now, I notice that some of them seem to be in the wrong area -- anything having to do with award travel, for example, obviously should fall under AAdvantage.
2. That problem hadn't occurred to me, but I think you present a good solution. (AA) at the end sounds like it would work best.
Slightly related, I've been bothered by the inconsistency in naming the articles -- some of them begin with "AAdvantage" while others dont, making it difficult to effectively organize a table of contents. I think we should strip "AAdvantage" from most of the titles, and just append (AA) to the end.
3. Ehh, I think thats more the result of FlyerTalk being Ad-supported. I think you'll be hard pressed to get them to change that, but who knows.
4. I agree. The best articles we have on the Wiki right now are those unique gems that we've developed ourselves -- the list of elite security lines, how to deconstruct a fare code, award stopover rules, the voucher FAQ, etc.
5. Sounds good.