I got a new one; I want a Mechwarrior game based solely around the Solaris Arena. It'll be about a common joe, an ex-merc, working his way up to the championships, think Cinderella Man and it will play a lot like any create-a-superstar mode in Madden games or such, but with alot of stuff to do out of the main season. You'll have working mini-games as you take on mechanics jobs, maybe hire and manage your support staff like personal mechanics to help customize your mechs (you can manage your mechs yourself but you'll lose time between signups for matches and it's faster to work with a team. This is to balance the lack of a training component like a sports game, so you're not just racking up shit tons of money between matches through the mini-games). And since I'm on a Find-A-Bae-In-Games streak right now, perhaps even a dating sim component to attract unique mechanics to date and marry to lower the costs of repairs and open unique mods to certain models of Mech. Perhaps that nice clanner girl can make that Timber Wolf's heat sinks slightly more effective.
It will also have very little to do with the greater politics of the Mechwarrior world at large. You'll have faction aligned unique fighters appear in the arena, but it's not the focus. That always kinda bothered me about MW4 Mercs, it always ended up with the choice between Steiner and Devion, when all I wanted was to listen to good old Duncan talk about that phenom blazing his way across the arena.