One thing I would really like to see is Onion skinning when it comes to motions on the timeline. I don't know if it's possible for motions that you've purchased, but it would be nice to have a mode where you can see the key frames in the view port so that you can get a good visual idea of how the motion's going to go. The thing I'm seeing is that when I'm animating, I have to cue the animation and look for mistakes and try to mark where they happen on the timeline and then go back, set a key frame, make an adjustment and go back play it again, and repeat.
It would be nice if you could highlight a motion and with a right click, onion skin the motion from start to finish at say, one second increments. You see a semitransparent representation of the mapped positions of the motion in the view port. Each semi-transparent image in the view port is a clickable object which you can use to edit the motion using the puppet controls to correct the position. This way you can do the whole motion at one time, and not have to step in and out of the timeline to keep viewing it. I would have it so that as long as you're in this mode, playing or replaying the motion starts and stops with the highlighted motion so you're not having to go back and forth on the timeline to try to get back to it once you click out of it.
This way you can stay focused on that one section until you're satisfied with it. It would also be a good think you could use to create motions to fill a space in the timeline. Let's say you have to motion clips on the time line with a gap between the two of them that you want to fill. You would highlight the trailing end of the first motion and the leading edge of the second motion, click Onion skin and you would get the ending position and the starting position of the clips as onion skin objects so you can step through the seconds between them to create a unique fill motion.