What I would want in addition to the recording system would be the ability to record multiple sets. That way you can have the dummy choose to react with some or all of the sets chosen randomly. It would help to practice against specific setups against different characters.
I would also like the ability for the frame time for the button presses to show as well. It helps to break bad habits of mine when I realize I’m pressing too early or late.
Finally, a mode that shows the hit/hurt/push boxes would be very nice. But, the recording system is top priority for me.