Well, Domination is a gamemode introduced in Plus that initially didn't have levels other than Blur's example. It's still underplayed with only a handful of good levels, but that doesn't mean any unique gamemode requiring new level designs hasn't got potential.

A 'Frog hunt' based mode could be played on some battle levels, depending on slope heights and vine dependence. If you make it so that frogs tongue can damage players and at least pass through the vines, I do see potential fun there.

Then again, it would be another mode ignored by the competitive scene and played solely in events. That's alright.