Simple fixes to improve the game 1000x -
1) Have Karaoke Kings' white skill only fire once he's stopped moving
2) Reduce the amount of energy Dungeon Man's 'Bountiful Basement' gives. When he was introduced it was fine, since at a low level it didn't give so much, but now we are level 155 it gives significantly more than intended by the designer.
3) Reduce the charge time (and, to maintain balance, damage slightly) on Moon Drake's white skill. Nobody, NOBODY, taps it early to fire off sooner with decreased damage. That's a useless feature. Removing that and reducing the charge time altogether would reduce the energy she provides, and also mitigate the 'screen freeze' issue.
Voila! We will then see more variety. Can't be more than a days' (10 minutes....?) work.