I think what went wrong with AutoAssault is it went a little too far in catering to soloplay. Actually, what went wrong is it didn't cater to group play whatsoever, if anything you'd level up slower having to team up with even one person. The PvP would've technically awarded you for grouping, but by time I got into AA the population had already dropped off enough I couldn't even expect to fight anyone if I joined a tournament.
And/or, I think AutoAssault is proof that what all the 'industry insiders' said about WoW was wrong. "World of Warcraft will just bring in more players to MMOGs, it'll be good for the industry." = Wrong, at least to an extent. More people may be playing MMOGs but the cost of entry is higher, and a lot of moderately successful MMOGs got obliterated because right here, right now there's only so many people to play. When there isn't enough people in an MMOG gameplay can suffer, and then you lose more people, and then it really starts to suck.