I 100% agree, no reservations, with the sentiment Mr. Mearls expressed to begin this kerfuffle. I run a Mutant Future (heavily houseruled) game, and I run a D&D 4e (heavily houseruled) game, and I play in a Labyrinth Lord (+AEC, heavily houseruled game)... and guess what. IN PLAY, the experience is exactly the same in all three. And of course, the experience is totally different. Completely unique to the game and the moment in all three, but while the game is going, we are playing a role playing game and occasionally rolling dice as decreed by the GM filtering the rules.
I could care less what the current version of D&D does, but I totally agree that the differences of edition are trivial compared to the commonalities experienced at the table.
In my opinion, the biggest differences between the editions are rules aimed at players who want to engage OUTSIDE of sessions. I would never ask someone brand new to RPGs to join the 4e game I run - I would ask them to join the Mutant Future game - 4e asks a much higher load of a player before the game even begins.
Old School Gamers Beware
There is nothing wrong with rules aimed at accommodating a player who wants to engage in the game outside of the session! In fact, a good DM should always encourage and enable a player's desire to participate outside of sessions. Good old school DM's do this without needing rules for it written in the game they are playing; if the player wants to get badass at using that cool scimitar they found, you figure out a way to express that at the table in a manner that works. The end.
New School Gamers Beware
There is nothing awesome about rules that make a player jump through hoops if the player doesn't want to jump through hoops! Many players will be alienated before the game even begins and they even get a chance to experience the real magic of RPGs in action.
The Point Is:
The final product of houseruling plus the old school game system of choice is far closer to the current iterations (Pathfinder, 4e) of D&D than most of the OSR would care to admit. And the actual play experience when the dice are rolling, the food is eaten, and the libations consumed - good fun was had by all, and to all who give a fuck about edition in any kind of negative way, fuck off.