I don't think anyone is saying that we need to focus on small wars to the absolute exclusion of conventional wars. That would be just as folly as our current void in small wars capability. But even the "Iraq is an aberration" crowd has to admit that we are lacking the small wars area and future small wars will happen. Therefore, whether the future brings more small wars or more large wars, we need to be prepared for both, as Merv Benson has pointed out in this thread.

While Barnett and Yingling are both correct, the situation is not as dire as it seems. The Marine Corps is small and adaptable enough to shift its focus to small wars and counterinsurgency and has a storied history in such conflicts, although mostly forgotten until recently. I believe the Marines can take on a greater focus in counterinsurgency without losing too much capability to conduct expeditionary warfare from the sea. In fact, the traditional expeditionary mindset and missions of the Marine Corps lend themselves to a counterinsurgency mission. The Army, meanwhile, can maintain its traditional superiority in conventional land warfare that its size, budget, and technologically-focused mindset are more suited to deal with.