I like to see a Wrath of the Lichking Remix or Warlords and what i like to see changed is a limited given to capes or harder raids/dungeons to avoid 1 guy running in and one shot everything and everyone.
Like Mists of Pandaria was fun till people started popping up soloing raids and dungeons.
It is easily fixed to one flaw I hated personally I feel adding Dungeon/Raid mode that disables the capes.