Anyone fed up of

Mobility is where you get your ass kicked by German GPMGs

This is correct.

IIRC Bars were so heavy that you can’t just rush around with them as if you’d hold a Grease Gun. Movement speed of an LMG gunner should be that of an MG or Flamethrower guy (so noticeably slower) and the time it takes to get into ironsight aim as well as weapon sway when aiming should also be increased to reflect that weight and make everything feel less arcade like.

XP for throwing smoke? Not gonna happen. The very same day, we would be seeing idiots with 9 men squads and large grenade pouches doing nothing but farming XP by spamming smoke at the spawn or in other totally useless places.

Not for throwing no, but dropping smoke and other players killing enemy yes…

Quite hard to accurately quantify. Smoke isn’t supposed to boost allies’ killing potential, it’s meant to negate enemy one. And you can hardly tell an algorithm how to reward you for enemies NOT shooting at your teammates.