I have tried running both TF2 and GES on Linux through Wine. TF2 was in the 10~20 fps range. GES ran 120+ solidly, except for drops associated with Wine, not GES. So performance-wise, I wouldn't be concerned.
Maps will need reworking certainly. Unlike Alpha 1.1 which had hard spawns, and Beta omg.lol which had NULL pointers instead of weapon spawns, B3 has actual weapon spawnpoints that spawn weapons according to a weapon quality value from 1 to 7. Thus, maps must be re-tooled to support the loadout system.