I always thought a Pokemon Contest stage from R/S/E would be cool.
It would act like a mix of Wario Ware Inc. and Pokemon Stadiums 1/2.
The fighters do "appeal moves" while fighting and get feedback from the crowd based on how good they do, what tactics and skills they use, how they use items, the timing of their moves, etc. A big screen on the back shows each combatant's appeal points.
The stage wouldn't change shape, but the theme would change periodically.
For example, the stage would have a red-colored theme and you'd have to do "cool" fighting moves to get points, while at other times the stage would have a green-colored theme and you'd have to do "smart" moves to get points.
Other moves could "jam" the opponents, like in an actual Pokemon contest.
Still not as annoying as Brawl WarioWare.
Wario Ware Inc. II.
If you fail, Wario goes "
OH MY GOD!"