I can fault COD in terms of map design in a number of areas but i can't fault it in terms of this.
Each weapon set has a area which it controls / best suited for. If you use shotguns it something you got to learn in order to do well.
Map design is a complex task......for a number of reason you got to make sure it suits all gamemodes, it plays a bit like COD and each weapon can do well. May not agree with all the choices they do but most of them make sense.
Problem is most people don't want bigger maps but more flank routes and this cause a key problem.
The gamemode problem appears.....certain gamemodes don't play good at all. Bigger maps don't mean good LMG maps......COD would have to change it map design in order to fix this problem. It also causes gameplay issues......which are pretty easy to work out.
Off the top of my head
Bakata, Interchange, Fallen are all LMG maps/Sniper maps
Very long sight lines and ttk is faster than ARs within LMG range.
AR = "all purpose weapon" not the best choice but mr jack of all trades. Good example is the ACR or MP7 both Mr average.
A reason why i have a AR class