Your idea of a challenge.

[Akujima]

well considering there are only 3 real methods of killing anything in an RPG

tank and spank
zerg
kite

i don't see what else they could possibly do

Wrong. You've obviously never played World of Warcraft. And yes I'll keep quoting it because it has very dynamic fight sequences, and nobody complained about how difficult they were. They sucked it up and realized they needed to work as a team to down the boss.

Magtheridons, Hydross and Lurker you did NOT tank and spank, you could not kite, and could NOT zerg. There was a specific strategy used to down each of those bosses. Grull the Dragonkiller and High King Maulgar, were also very dynamic situations. They did involve tanking and spanking to some extent, but that's not ALL the focus was on.

And DD in WoW had the toughest job -> They had to watch hate. Why? Because if the boss turned and started hitting them, they would be pushing up daises, lowering their overall DPS.

EDIT: It's time to face the facts, and learn from the pro's. Take from their successful concepts/idea's and expand on them.