First off, the Small Wars Manual has never been dusty,
But having the Marine Corps specifically train for large scale counter-insurgency training, will give us a niche role in long-term sustained operations against an enemy we expect to be present for a long time.
The MEU's are standing units, that after every deployment rotate out and in a battalion/units from within the Regiment, while MEB's are not, with only command staff manning the units and are organized specifically for conflicts.
The USMC in respects to TO&E, especially in the reserves has changed alot since the end of OIF 1, the active duty LAR bn are each adding a line company of LAV's, while 4th LAR (reserve), has converted two tank co, to LAV co, the remaing tank co, were converted to Anti-Terrorism (Light Infantry), giving the Reserves 1 tank bn, also, Arty Batteries and AD Batteries were also converted to Anti-Terrorism Units, and on the Active duty side they are adding two Infantry Battalions.