A Mechwarrior Game--IC
I would think the best way to keep it from getting bogged down in 'Mech combat is to prevent the PCs from starting as 'Mech pilots. If you want them involved in warfare, have them do so in another capacity -- maybe infantry, or part of an armor division.
Or maybe put them behind the scenes, with technicians and medics and other support staff. Let them deal with cleaning up the aftermath of warfare, rather than man the front line.
Or pull them away from direct conflict. Make them in charge of the tactical side of deployment, managing entire lances or battalions. Give them the logistics of handling a 'Mech unit, or a mercenary team, and put them in charge of the Big Picture. In fact, if you have a way to abstract the results of a conflict, this might be preferable to the minutiae of tactical fighting.
Or scale it back down even further. Make the PCs recruits for one of the big houses, going through an academy to learn 'Mech piloting. Let them take practice runs on piloting and gunnery and things like heat management and sensors. Then, maybe, throw something dangerous at them and leave them scrambling for a way out. Maybe a rival House attacks the planet.