Idea.
Use MMB for PAUSE/RESUME operation. Spacebar is cool, but I think having equivalent of it on mouse would be even cooler.
I'm just wondering, how would this improve the game?
1.You can play more without touching keyboard.
2. Pausing is easier - no moving with cursor or reaching for keyboard.
Cigarette, you know I love you but leave my middle mouse button alone! ^^
Not exactly a bad idea though but in my humblest opinion it's most irrelevant, sorry.
there are zillion applications to redefine keys, ever if game does not support keymappings you still can map anything to anything for specific application with such tools.