I think this would be useful if it was just in town. I waste time changing my skills all the time, it would be a great improvement to just be able to click a little button and be on my way. In battle is too risky, i think it would make it too easy.
Well, if enemies can do it too, thna it wouldn't really make it easier. I'm also completely against being able to have any ability to do this in battle whatsoever, but It'd be nice to be able to do it outside of towns still.