It's getting old sacrificing our suits ability to use equipment for 2 Heavy Weapons and items that don't exist.

Sentinels have a Heavy Grenade slot.

The reasoning we cannot use equipment is due to the suits resources being diverted to our large weapons and powerful grenade.

One reason only has 2 weapons, the other reason doesn't exist yet.

Correct. The heavy grenade would fit into our Heavy Grenade slot.

I want to trade them the Sentinel Damage-Type Resistances for extra Racial Weapon Ammo Bonuses.

That aside Large Grenades and the cake are both lies.

Armor Heavies are in an EXCELLENT position.
Like, literally, you don't need any more better stuff.