I would start by completely deleting everything Ion ever did from game.
The leveling experience would be made to last a LOT longer... 30 days plus.
Make the crafting viable for this longer journey.
I would do away with the various difficulties. There would be Normal and Heroic Dungeons, and one difficulty raid with some hardmode options. Perhaps Heroic dungeons would have additional or maybe even different bosses.
You would have to do a lot of Normals to be able to do Heroics... you would have to do heroics and craft, and get reputation to prepare for raids.
Gone would RNG gear tokens and titanforging... back to deterministic loot, with more sockets, crafting profession perks like sockets/fur liniing/etc...
People would has a BiS list, or a preparation list and go farm those instances for their gear. There would be Valor/Heroic badges for fill in pieces.
Epics would disappear from dungeons except maybe last bosses of Heroics. And even then raid pieces trump them every time.
Tier gear would make a come back.
A lot of this account wide crap would go away... just because your main is exalted with The Scooby of the Doos, doesn't mean your level 5 alt is too.
Instead of pretending that we were listening and then completely blow off every comment as if it were never asked.... we would just be honest. "This is the game now... if you don't like it... play something else. We're passionate about the game, and will always put FUN first."
Most importantly.. I would do away with LFR, dungeon finder, and instaport into dungeons/raids. If you cannot be bothered to play the game by being a part of the world, then you shoudln't be playing the game at all. Simple as that. Join a guild or be happy with the leveling/world content.
This is an MMORPG... or WAS. now it's more of an MMO-ARPG with a lobby based queue system instead of friends.