Oh boy.Originally Posted by Blizzard EntertainmentThere are no level 90 regular dungeons.
The Mists of Pandaria heroic dungeons are easier than the Cataclysm heroic dungeons.* Once we made that decision, we thought that having two versions of the level 90 dungeons (normal and heroic) didn't make sense because they would be very similar in difficulty and offer similar loot. We thought about calling them something besides "heroic," since heroic tends to mean hard to a lot of players, but we also needed to call them something, because some dungeons like Temple of the Jade Serpent have a lower-level and a level 90 version. We thought about calling them "level 90 versions" but figured "heroic" required less explanation. (We also could have dispensed with lower level dungeons, or made lower level versions of the level 90 dungeons, but we felt like both solutions were just to make the nomenclature of "heroic" more clear, which seemed like bad reasons.)
TLDR: Some Mists of Pandaria dungeons have lower level and level 90 versions. Others just have level 90 versions. In both cases, the level 90 versions are called "heroic."
* - If you like very difficult dungeons, Challenge Modes are targeted at you.
Welfare epics here we come.