Have you had a look at the Source Movie Maker from Valve? http://www.sourcefilmmaker.com/

It's by for the most interesting development for animation that I've seen for years. In about an hour I was able to produce 15 sec of reasonable good animation the first time I used it.

Their process is more akin to Photoshop than anything else as it's a destructive process rather than procedural.

I found it quite enlightening.