Each boards bosses are testing different strengths. I love the theme Whomp and Bob omb has.
Lakitu/Wiggler: Action and moving around
Whomp/King Bomb omb: Anticipating what your opponents are going to do next.
Dry Bones/King Boo: Puzzles
Cheep Cheep/Blooper: Accuracy
Spike/Chain Chomp: Reaction Time (Spike:Golden Hammer, Chain Chomp: Picking correct cannon.)
Bowser Jr./Bowser: Luck
So, what do you think? Am I correct?