"It seems to me like it's a large part of the playerbase that didn't exactly enjoy the changes to gearing and dungeon difficulty. "

Yeah, it's called quitting, which many of us did a year ago when running a heroic felt as enjoyable as ramming your head into a brick wall. Many did not get the message that WoW realized the error of its ways and returned to the Wrath model and still have yet to return. Maybe they'll never return, and whose fault is that? Blizz for making heroics so unfun, or the hardcore jerks who complained in the first place that Wrath had been too "easy"?

And I, too, would be interested in knowing how the OP geared up so quickly. I've run four DPSers through the Twilight 3 and into LFR but it took a few weeks worth of heroics to get each one up to the 372 required to enter the LFR. Most who had dinged 85 from questing had an average ilevel around 325, maximum, and had no chance at all of entering even the Twilight 3 without putting on several pieces of crafted PvP gear, which felt rather shameful to me.