It sounds fun in theory but I can see some problems, mainly the fact that complex actions would be harder to do. Moving various body parts simultaneously is very useful but with the control system we have it wouldn't be as easy in real (well slow mo) time.

However I have a suggestion as an offshoot of this which may or may not be of interest to anyone, what if the two players had separate turnframes and you could change (midgame) how many frames go by for you depending on the situation. Say you are sparring and you want to fine tune a punch you would lower the tf to say 5 and go in slower while the opponent can choose however many frames they want to go by (like someone used to lenshu or something they'd set it to 30) this could allow for more variation and skill. now there's a problem with this suggestion, the waiting time, if your turnframes are higher than your opponent you would have to wait for them to complete their move to catch up. If you have a 50 tf move and the opponent has a 10 tf each time they would do 5 turns while you wait and fine tune your next move until they have 50 frames passed as well, you wouldn't be able to see how many frames your opponent is moving. I'll cut this short as I feel like I've droned on and don't want to sound repetitive. I tried to explain what I mean as best as I can but if there are any questions or if I need to elaborate I will do my best to clear what I mean up.