I wonder really. Think back about doing wotlk heroics in quest/normal blue gear. Were they really that much easier back then? I remember running dry on wotlk heroic bossfights at the very start, having plenty of trouble to keep the group up. I rememver even wiping on HC Old Kingdom in full epics with an idiot tank charging into 3 casterpacks and getting one-shot.
Thing is, now my guild group started gearing up and we've gathered full 346 gear combined with a couple of epics we can already speedclear most heroics, cleaving our way through wotlk style, without relying on any form of CC. Bosses drop in 2 minutes and this is only in blue gear / first tier epics. Seems like it will go exactly the same path as late wotlk.
Isn't it just that people got used to outgearing heroics by such a big margin, with too easy to obtain epic gear, that having to do them in intended quality gear feels impossible all of a sudden? Feels to me that the only thing that changed is a reset of gearquality, not the big leap in heroic difficulty as a lot of the players think it is.