I guess my fundamental problem, in a nutshell, is that you're effectively trying to majorly limit or eliminate major portions of the game: namely player substitution and defensive playcalling. How would people feel if the same were somehow accomplished on the offensive side of the ball? What if you couldn't change your offensive personnel or could only make limited adjustments on offense to match the defense? What if, as a result, nearly every game were a low-scoring affair? My guess is that people wouldn't be quite so supportive and would be calling for a major rule change. Why? Because people are shallow. It's the same reason people called the regular season game against LSU two years ago a snore fest and why they like watching West Coast QB play. For some reason, people just like gimmicky, fast-paced, and high-scoring offenses.
Me? I like a chess match between two teams and two coaches. To my mind, the HUNH is like playing chess, but taking away half your opponent's pieces. Sure, in this case it's legal, but I just question whether it's truly good for the game.
Like I said though, I doubt it's going away anytime soon, so you either adapt to it, or you lose. It is what it is.