First... they need a new engine.
They need to cut all the shit to get back to the simple old style type game.
too many overpower guns, guns with a higher fire-rate should have some serious recoil.
they shouldn't add stuff like "proficiencies", proficiencies help the guns get overpowered. that's 1 reason we have overpowered guns.
perks are way too overpowered. Id like if there were no perks, so its up to the players experience to help him, not some assassin crap perk.
I'd continue but I don't have time to write 500 more things that are currently wrong and should be fixed...etc.
I would like a CoD4 remade with new graphics + fixed all hacking problems + with more maps + old maps. Would be fun.