Tacair training is an inherently high risk activity. Human error is the obvious causal factor in this one. Coulda been a crap admin join by a 25 hour wingman with 2 hours in the last 30 days or coulda been a training rule violation during 4x4 BFM with 8 2000 hour dudes. We just don't know right now.
Whether it can be walked back further to some of the things being talked about is going to be on the shoulders of the mishap board. The Navy and Marine Corps do not share the information from their aviation safety investigations.
The Fiscal Year is only one month and 9 days old and we've already had a Class A mishap (>$1,000,000 or loss of aircraft or death/permanent total disability) on EVERY airframe except for Harriers and Cobras.