Yea, Mega Man.

Mega Man Legends, Flutter vs Gesellschaft is one of the best bosses ever. It starts with them dropping a bunch a ships. It's just a stall tactic so the main ship can catch up. Then you're fighting this giant airship. But you have a speed a movability on your side. You flying around targeting it's weak points. And then phase three happens and you're the giant target and they're the fast enemy zipping around. I love that role reversal. And there's the frog boss in the lake. The giant mining robot. Bruno in the Old City. And the final fight with Juno.

And on Mega Man, Zero 3. All the bosses were fun to fight. And the final dual against Omega. (SPOILER)Which is Zero with his moveset from X4.