Could be nice to have a more strategic raid system in addition to the existing one without tile damage.
Tiles just to charge mana, where rainbows have almost the same chance to win like stacked attacks. Possibly that would be more challenging. Everybody has to set up teams upon special synergies and not put 5 of a color to kill by tiles.
Could be called rainbow mode with a separate ranking.
The +20% def bonus could be deactivated to balance the missing tile damage and a point-based scoresystem could easily be calculated by counting in the teampower.
Strategy vs Mono and both won’t harm each other…