I would love to see a tribe or "cult" that worships some sort of "biotic being/god". Like battlemonks they could train the arts of biotic combat and bring the mass effect manipulation to a point, where they basically become supernatural, putting that insane force in every kick and punch, jumping several meters in the air and gliding down gently. We've seen such things before, the biotic fist in ME3, Samara levitating with mass effect manipulation and stuff like that.
I just want variation. I don't just want volcanic, storm and ice planets, that have life on it, which was unseen before in terms of real life, I want some "on the edge" science fiction, almost like fantasy. In the trailers, we've seen rocks and isles flying above the ground and creatures, that flap their wings like once per 2 seconds and they slowly fly through the air, that's exactly what I want. It let's me speculate, that Ezero could be a common ore on these planets and have influenced creatures and even plants or who knows what. It's radiation could effect creatures, and they adapted, even the stones and materials in the ground could develope strange gravitational forces.
Reality sucks, why not sprinkle some science fiction/fantasy on it?