ToT made me quit heroic raiding. I see a lot of 3d/week guilds (who typically raid 9 to 12 hours a week) who dropped a massive amount of ranks during ToT, with nearly the same roster as before. On the other hand I see a lot of guilds who used to be way lower in ranks, but who would raid 4d+ a week / much longer sessions - and who climbed the ranks. The reason I see is that the big raids combined with tons of trash takes too much time to reclear, and definitely in 10m where its harder to get an optimal loot distribution, you need those clears on hc to progress. And the longer your reclears last (since you kill more hc bosses), the longer wipe time you typically need for the next bosses, as they get harder and harder. Most of these guilds have been non stop progress raiding since september, and it eventually makes a lot of players tired.
Cata was for me the ideal raid expansion: massive opening raid (combined) with challenging bosses at the start of an expansion. Firelands which was a short instances with interesting bosses and a massive challenging end boss, some time off till DS, and then another short instance, with a challenging spine prior to the nerf. And plenty of time off till next tier (a bit too long). So a big opening raid is fine for an expansion, but follow that up with a raid that is as big, and then again ... that's too much imo for those guilds with a relaxed schedule, but who clear all HC bosses prior to nerfs (3d/week guilds). That is as far as raiding goes.
What puts me off the most is the crazy trinkets and legendary items. Everyone can have the legendary items, and thus everyone is forced to keep up. There is no real way to take a break / reroll. The crazy trinkets create such a difference between the haves and have nots, that it kinda determines if you do good dps or not. Which brings me to the rppm system: this is for my spec (ele shaman) the biggest bullshit ever, it turns trinkets into a complete passive experience. Of course it's lots of fun on my lock. But the difference between a good and a bad ele shaman has never been so smaal to my experience.
So no, I absolutely don't share the sentiment of MoP being the best PVE expansion. Too much, too long, too crazy.