I like the final deflect upgrade because it REQUIRES there to be archers, and it REQUIRES there to be a threat of the deflect missing (this has happened to me), and it REQUIRES to use three whole points just to get it.
and while it's true that it could be sued on any enemy, it there are currently only swords and bows. however, when doborog DOES add more upgrades, this upgrade could turn into a tree of being pick up a certain weapon. also this drain energy to use, making it a little less OP :)