I think if theres a problem its that alot of training in the US tends towards a rather simplified version of kickboxing. Hendricks had I think developed pretty good striking along these lines BUT he wasnt prepared for the test of someone like Thompson.
The ironic thing when talking about "evolution" of striking in MMA is that I actually think things took a big step back in the post Pride era when training shifted to the US. You look at Fedor for example, a grappler who learned to strike he the level of technique he picked up was so much higher because he wasnt learning "Boxing/MT for dummies" he was learning high level boxing and kickboxing techniques from either his own trainers(including an olympic level boxing coach) or camps in holland.
Its taken years and guys like Hooft and Bang who are starting to move beyond the standard cookie cutter striking training thats starting to reverse that.