"So-called capabilities-based approaches to force development and constructive simulations that validate those approaches ought to be abandoned in favour of clear-headed thinking about contemporary and future conflict. Afghanistan, Iraq and Lebanon reveal the need for balanced joint capabilities and additional capacity in other agencies to assist in postconflict stability and counter-insurgency operations. At the operational level, forces must be capable of conducting counter-insurgency, stability or state-building operations. At the tactical level, forces must be able to fight under conditions of uncertainty and be employed in sufficient force and in the right combination to establish security and overwhelm the enemy in their area of operations."
While I agree on one level, I think McMasters might be looking down the wrong end of the telescope. If you continually ask the wrong question, at no time do you get the right answer.

Forces should be capability based. What is always missing is a clear doctrinal understanding of why the capabilities should be limited. The US problem has always been to assume that military power comes from maximising capabilities. Obviously it does not! Sorry to state the obvious, but it needs to be stated.