yeah that's how i see it also, as a back up wepon, in case you need to hit the target as it runs away.
A push heat mech is a good decent build. Another variation is the BBQheater build, 2 flames, and another close wepon shotgun/sword...but that is just energy dependant... and the way the heat wepons are now... they overheat u more then the oponent... you need alot of heat and alot of energy.
The most viable build i have seen so far, is Flushy's build and Earthy's build, they are energy independant, that work fairly well. The only downside of those, you need alot of "exclusive" wepons and a must on the myth plates and protector.