I enjoy the general structure of Metroidvanias but most of them rely on combat mechanics for the micro-challenges in each room or boss. I like the exploration, backtracking, progression and unlocking previously inaccessible area.
But combat isn't the only mechanic that could be present there. There are examples like Ori and Toki where combat is de-emphasized in favor of movement/puzzles, but they're still 2D platformers.
I want to see a metroidvania game based on racing. I enjoy driving/racing games and would like to see those mechanics provide the micro-challenges for a metroidvania. Boss fights would be setpiece races, earning XP would be small things like a time trials, stunts, or precision driving. Unlocks like drifts, speed boosts, etc.