Literally this is how combat worked when I was playing H&H while asleep.
Each of the 1-5 keys had their own SEPARATE deck. So 5 for example I had just a single card of Take Aim. 4 for me was a 3-card deck of defenses.
I don't know if it's a good idea to implement, but it certainly made combat easier to control while expanding on the number of moves used.