I second basically everything Uberlou has said. In particular I've found myself accidentally creating new keyframes all over the place a ms or so out from the one I'm trying to edit.
It would be nice if there was a way to copy and paste a bone and sprite group for all keyframes. Say for the instance you have a limb, you animate it perfectly then simply want a mirrored copy of that. I'm currently doing this by moving through every single keyframe copying and pasting the limb/tranforming it to mirror etc. Would be nice to have a better solution for this.