im a heavy and i ******* hate heavies who run light weapons... please just remove the ability ccp or make heavies less efficient with light weaponry

People are still whining about it? GET OVER IT
Light weapon slots can support sidearm slots, therefore it makes sense for that heavy weapon slots should be able to hold light weapon slots. "Bigger" slots can take in smaller weapons.
The heavy suit itself is balanced by low sprint, low strafe, low stamina, no equipment slots, low scanning abilities, huge signature profile, and huge hitbox to counter the HP they have over medium frames; therefore, I don't see why they should only be limited to heavy weapons. You guys seriously want to limit heavy suits to 2 weapons?!

Why? Logi's don't need more slots that assaults to play their intended role? All you need a skills that boost your equipment use.

You are not combat units. In fact the logi suit could loose its grenade slot. Logisitcs don't need them at all.

While that's true of the game now, it'll be different when Sentinels get 10-15% more EHP because of the resistances. It will very much likely become a problem.

IMO, the fix would be:

Basic Heavy Frame = Heavy or light weapon, your pick
Sentinel = Heavy weapon only
Commando = Light weapon only

The suits would all remain relatively balanced in that case and each have a defined use and limitation, without the Sentinel becoming the new Scrub FOTM.

ED: I will say, I hope it doesn't turn out that way, and we can all live with the few light weapon sentinels getting their kicks without becoming FOTM (likely because former slayerlogis yelling "OMG SO SLO"). But I'm worried man, I'm worried.

reduce magazine sizes and/or fire rate for weapons that are not in their appropriate slots.