It didn't work very well anyways. You had to severely limit the C# features you used in order to target Flash. The majority of plugins didn't work, etc.
With their recent announcement with Facebook to make the Unity web player plugin experience more pleasant, this is much less bad news.
And hopefully they're working on an HTML5 target as well.
So, just another nail in the coffin for Flash at this point.
I totally agree. I would rather love to have Flash as a build platform right now. But, have you tried using it with Unity? It was terrible.
I'm pretty happy with them focusing on making the web player install easier / more seamless. That will achieve the same goal and be better than running the game in yet another platform that can have its own bugs.
I didn't understand why Unity bothered trying this in the first place, so it's not surprising they gave up. The obvious places for Unity to go would be WebGL/ASM.js and NaCl (which I assume would be borderline trivial for them to support). It would be awesome if they revisited their "JavaScript" implementation and made it a bit less unpleasant to work with while they're at it.
According to Eich's talk Friday, ASM.JS is around 2x slow as native, which is acceptable, but should improve. Before that other WebGL solutions were 10x+ native.
With their recent announcement with Facebook to make the Unity web player plugin experience more pleasant, this is much less bad news.
And hopefully they're working on an HTML5 target as well.
So, just another nail in the coffin for Flash at this point.