It finally occurred to me just what was so striking about the Inversions in AXIS.

The Inverted heroes were basically parodies of the less favorable interpretations many fans have had of them over the last few years. Many, myself included, have been inclined to call out the Avengers as (at least bordering on being) hegemonic fascists who think they have some special right or license to boss around everyone else in the superhero community despite their own failures and dubious actions. Many have looked to the X-Men becoming increasingly insular and distrustful of non-mutants and called them out as racists prioritizing the security and well-being of their own people over the good of the world at large. Thanks to AXIS, those particular interpretations became canon; the Inverted Avengers did become straight-up fascists who wanted to control and dominate everyone and everything around them, and the Inverted X-Men decided coexistence with humanity was for suckers, waging war on and even seeking to wipe out the human race.

That was the twisted genius of Rick Remender and AXIS. He took everything fans have been saying in criticism and critique of the Avengers and the X-Men, and gave us a look at what the Marvel Universe would be like if those criticisms really were (or became) true.