I just had a quick look to it. I think it has a good potential to gain a worldwide position as a standard IDE for HTML5 stuff.
When I start diving into HTML5 & Co. I would do it with Sencha.
BUT , yes… nothing replaces Flex
as a Flex fan I’d like to say some words about that topic.
1. Flex is doing very well. Actually, I developed and published three Apps to the Android & iOS Store. It was so much fun and the development process is very cool and powerful.
2. U can really develop anything if u like. Games (Stage3D on Mobile) or Apps in any kind of size and league. There’s enough amazing examples and works, i don’t need to tell ya about the possibilities so. (There’re many Native Extensions, also)
3. FalconJS is going to be very cool. Just have a look on Jurangoo. They’re examples where Box2D is completely regenerated in JS. And whole games done with Flixel engine also converted to JS with Jurangoo.
If the smart guys from Jurangoo can do such a great thing, then I guess hardly that Adobe/Apache can do it also.
So were’re the problems or doubts?
We can do Apps, Console-like Games (even for Mobile), Web (HTML5 / JS) and also standalone Desktop Apps all with FlashBuilder (MXML or pureAS3).
It doesn’t really matter if Adobe or Apache gonna continue the development process. But the fact is that it continues!
And i believe that it’s just a hype with that whole HTML5 stuff. I’m sorry, but I want RIAs, GAMES , Entertainment & Interactivity. HTML5 is far away from all of that. And if i want to, i can run my compiler and generate the HTML5 /JS-version of my as3/flex stuff…
ByTheWay: Have a look on Flash CS6 & CreateJS, could be interesting.