I never dragon cancel the medium or hard dragon dance because as you said you are vulnerable. I like to use the medium frame trap to continue pressure or go into throw opener if close enough.
I have also started cancelling the overhead light dragon dance with a dragon into a low or throw opener which tends to work really well (actually tech I picked up off one of LCD’s streams so credit goes to him) it’s tricky to get down but trickier to block.
Also something which I don’t see many people do, is after a wall splat the norm is to reset with the throw opener. When you get your opponent used to this so they try to tech, instead of jumping with the floaty jump I now use light dragon dance as it’s throw invulnerable at frame 5 so if timed correctly works great as a reset instead of the jump.