Idea sounds fun, better as a new advanced mech. Can give the sim/'realism' fans more individual weapons management.
Example new mech: C class double heat cannon. It'd make sense to install coolants for each cannon on this large mech (move slower than brawler, but fly faster). It can do high burst with both, but each overheats fast so no spamming. Alternate shooting could last slightly longer than other mechs, at the cost of low dps & always on radar.
2nd example: tie this double heat gauge mech with a heat mask ability. Ability/mode allows mech to stay off-radar, as long as 1 of 2 gauges is empty, with time or mobility tradeoffs. This allows a slow C mech to flank & hide. Though enemy's hit direction will still show flanker's general direction, and this mech isn't invisible like pred.