LFD, This ruined the ability of everyone running to a dungeon, meeting up with a bunch of people and fighting opposing factions.
"Stand's waiting, then all of an sudden a Undead Warlock comes with a group of friends. You try to survive until your friends arrive, then fight them or run into the instance because you're scared." This engaged epic world pvp and allowed people in the world.
Flying Mounts ruined the WORLD aspect of the game. World of Warcraft was exciting because we got to see new areas in the world to explore.
Cataclysm revamped an entire world that we used to love, but they decided to hand out flying mounts at level 60 and increase the rate of quests, not only did this force us to skip over alot of great towns, forests, villages, caves, but it also pushed us out of the "NEW" questing zones alot faster because Exp was too low. Removing flying from kalimdor and eastern kindgoms until level 80, instead of 60.
Heroic Mode made raiding so basic.
In ulduar, we had to do special things to unlock heroic mode, then ICC comes out and boom, Heroic Lichking in a flick of a menu switch.
Yes, they've added elite modes to fix this problem, but it doesn't really FIX the problem. This game is becoming nothing but menu's