Talking about a new framework from scratch I think haxe will be better option. I'm sure Nicholas will support new avm as soon as he can. Haxe has better performance too.
Regarding API we have the flex API to use as the first draft and change if things are not what we want. We'll need to know what's the starling replacement in haxe. This could be started today if we want. When new avm comes out we will need to make some refactors but I think that haxe hopefully could abstract more of the changes. To start I think it would be great if someone that already work on decoupling UIComponent could share the work so we all could learn from that experience -- Sent from Gmail Mobile