I would agree but Sledgehammer haven't truly been able to show us what they have to offer yet.
Everyone jumps to MW3 which wasn't their game, they assisted on it, they were a smaller studio than the already quite small IW at that time.
Does no one remember what SH games were working on before MW3? A dark 3rd person Action Adventure Call Of Duty game.
This is a studio with a totally different background to the 2 studios working on the other games, while Sledgehammer haven't officially made their own full title yet, the 2 studio heads came from working on Dead Space at Visceral.
It sounds cliche saying "We haven't given them a chance yet" but what I mean is, they literally haven't had a chance to give us what they see in a Call Of Duty title, MW3 was just them following orders.