any reason why i WOULD NOT want to use AS3???

AS3 has a learning curve that comes along with it, which involves the same sort of hair-pulling and sleep loss that you might have had when you first started using AS2.  If your file involves alot of different complex actionscript and built-in functions, then you might want to weigh your schedule against the time it might take to learn enough AS3.  If the actionscript is fairly simple, say just a handful of similar/simple commands, then it should be easier to manage.

If the only thing driving you to use AS3 is the currentLAbel bit, one thing you could do if you need to know the current label is to have a variable that you assign that value each time you enter a particular label's zone, both directions if need be.