According to what I've read about Cope India there is an even more important "lesson learned." The USAF aircraft suffered worse-than-expected loss rates largely due to a lack of supportive air intelligence. For example, the USAF is used to operating with AWACS and a full panopoly of national technical systems and theatre backstop, etc. In Cope India there was more strictly "fighter on fighter" engagements (or with minimal ground control) and the US pilots were not able to leverage their usually superior intelligence (provided by AWACS, etc.) into decisive victories. One of the lessons was apparently: Absent the typical U.S. superiority in intel/information, U.S. aircraft and pilots will have real problems 'dominating' developing nations --- many of which are acquiring good aircraft and training very good pilots.
Of course, this ties directly into the F-22 funding question. If we buy more F-22s, how much *less* are we going to be able to buy in terms of AWACS, ground radar, data-links, etc.? Even with top-notch electronically scanned radar, fighters are vastly more dangerous when armed with data from theatre and strategic intel sources. Would it be better to go with F-15s and complete support, or would the F-22 and skimpy support do better? When trying to size up airpower you can't just look at the fighters.