I recently ported a ~9-year-old game from Flash/AS3 to Haxe. It was an amazing experience, plus I got it to run on all kinds of crazy platforms and added a bunch of new features.

I'd advise anyone wanting to scratch the Flash itch to see if it is a feasible thing. Won't be straightforward for all applications, but I found it almost cathartic.

Haxe is a gem of a hidden language. It's just too bad the community isn't gigantic and the tooling support (IDE) is rather lackluster. I've become quite fond of it (especially after working with it nonstop for months in my free time). I recommend everyone check it out!