Will there be an AS4 / AS 3.1 anytime soon? I really do not want to buy CS5 if a CS6 is going to come out in like a year or two and have a new AS version and then feel stupid for upgrading at a poor time.
Oh man, I hope there isn't an AS4 anytime soon. I just started studying AS3, and besides, I don't see any reason for a new version anyway. Don't fix what's not broken...
Overloading isn't compatible with dynamic resolution of calls and first-class functions without delegates. AS instead has default arguments which covers cases where overloading would actually be useful.
Everything else you could reasonably want is given by haXe.