I have always wanted a Battletech MMO. I don’t even know what precisely it would look like - but something set in that massive universe, where you could join any of the Houses or merc units - quest around for lost Star League hardware and tech, and of course wage war for territory across the inner sphere. You could earn planets to try and develop and defend - kind of like what happened to the Gray Death Legion.
Sets up perfectly for some global events, and of course expansions into the clan invasions (and the eventual invasion of the clans)