COTS is the way ahead. When the C17 was leased the deal was that it was operated as per the original boeing design and the way in which the USAF operate (although obviously lower down the food chain i.e. commands etc they managed a small amount of tinkering to ensure that it was operated much below it's capabilities)
This aircraft works and works well. does the job, very rarely goes u/s and gets praise from everyone who uses it. Unfortunately most things do get "tinkered" with. Why is the RAF the only organization in the world where the following happens. "we need a dog" .... ""lets buy a cat and give it surgery"