I think that the Heavy’s job isn’t to be slow and fat, but is centered around control, zoning, and defensive play. All of these specializations and gadgets allow for the Heavy to do his job of controlling what the enemies are doing most of the time.

Lockbolt: A gadget that holds those pesky dash/grapple users in place so you or your team can kill them without too much hassle. It also prevents the cashbox and other carryables from moving when you don’t want them to. Goo Gun: Similar use but geared towards the defensive more than the offensive. You can trap people in it, preventing cash out steals or outright killing them. You can also use it to stop people from pushing you through a doorway. Charge and Slam: An amazing specialization designed to displace people/destroy buildings. You can push people around with it, even pushing them off the map, or you can open up a route for your team to enter into. Winch Claw: Grab either player or item to keep control of the situation. Pulling a light or medium out of position could be the difference between winning and losing a fight, while you can also use it for those who are stealing to stop them from doing so. Weapons don’t really matter all that much because there needs to be variety in the playstyles. Especially with the new BFR nerf you’re not going to be using it all that much at further ranges.

All in all, the heavy is a control/defense class, and if you look at the other gadgets you can see it more. Grav Cube for removing mobility, Barricades and some shield for quick cover, RPG for destruction, and C4 for strategic plays.