I thought Gear Tactics was kinda of a "my brain explodes in potential" for other games in the same format. Since XCOM has so many mods that let you add equipment from all kinds of games, it's easy to imagine
Like a Metal Gear spin-off where you run and manage a PMC company and do stealth turned based tactical operations. Peace Walker and V had a REALLLY addicting mini-game centered around this. Just expand it, and put in a full rendered 3D battlefield.
Or a HALO ODST focused spin off, whereas you control a group of Helljumpers against the alien threat.
Or a Resident Evil one; could be controlling Blue Umbrella and managing it's day to day operations against bioterroism. Put a heavy emphasis on Survival Horror aspects to add to the tactics formula.
It could be applied to any military-focused video game, and I think it'd fit for most of them.