I have been using/learning haxe.. and I am now beginning to think the question should really be:
Does anyone else think coding AS3 is kind of pointless?
I mean its not a big leap to haXe from AS3 and probably not from AS2 if your just working with flash. So if you divorce graphics and code I do not see the advantage of AS3 apart from the larger user base.
For instance if I load a movie into the same ApplicationDomain I can create a new instances from the loaded movie by its name and cast it to MovieClip
var mc: MovieClip = cast( Type.createInstance( Type.resolveClass( nom ), new Array() ), MovieClip);
Notice the use of the generic 'Type' class, now this looks messy, but doing this in AS3 is more messy, but in AS3 I have to use flash specific and less logical constructs, my mind is constrained to think always in flash terms, haxe allows me to think more in terms of general code and not get too caught up in code that will be useless in flash 11! It also helps me see areas of flash that are ugly and I can package them so that I can work in more general platform unspecific terms.
Haxe also has interesting lightweight structures that allow for cases that are marginal for class such as typeDef and enum.
I understand why you might consider using flex but AS3... can't really see it, haxe just opens up so many more future options. I am working on some work flows, soon I will put together a tutorial that may help you with switching to haxe.