I'm not sure if this was suggested elsewhere, but maybe a mode where the next wave starts where the wave starts when the guy in last place finishes clearing his wave? Maybe limit interest to proccing like twice a round or something? (sounds complicated :x)
As Ele TD noobs, my friends and I just want to chat while making complex or simple mazes, but usually the simple mazes clear too fast and the guy with the complex maze gets quickly overwhelmed.