The heat cannon is a slow, mid to long range weapon and doesn't make sense when paired with a class like infiltrator, especially since it has a GL launcher that fires in an arc that is relatively hard to hit someone with unless you're somewhat close to them to begin with.
The heat cannon gives the mech an odd undefined direction, that would have been better suited to the sharpshooter or sniper class, as it is primarily at a distance majority of the time, where the heat cannon is best utilized.
Thoughts_
Edited by Patrick Bateman, October 25 2012 - 11:20 PM.