I've read in the Spriter forum people asking for mesh deformation and some mentions that it will be released in Spriter 2, I also dont remember seeing it listed in the current features so I'm guessing its still not a supported feature.
Spine would be the best of these applications, but at about $300 I'd go with the free one that in my opinion is in the second spot even with the flaws it may have.
Yeah, for me FPS is kind of important since I'm used to it, and if you need to work on animations for videos and cinematics you wouldn't export the output in an arbitrary way.
By the way, thanks for mentioning this, how does the delay per frame work in visionaire?, I mean, how do I set it on each frame?