The minimum range system already covers the basic tactical use of that style weapon. You can call it somethign else, but it doesn't really change it.
Ok. It's boring. I was keeping some of the crazy stuff to my self... but if you insist ;)
Area of effect weapons like hyper-flamers that hit 5 hexes in a line or hexes adjacent to the mech.
Subterranean units
Sprayers that create columns of particles that act like chaff and mess with missiles that pass through them
Anti-building munitions (not so crazy)
Missiles that can take indirect routes to the target
Launchers that can split fire between targets
Vehicle turrets with infantry compartments that can detach and act as a fixed position / pillbox
Weapons designed to alter terrain
Narc pods that temporarily simulate sensor hits
... stop looking at me at like that.