Hyjal can literally be 100% completed
Deepholm works you can get Exalted with the reputation here and buy the enchants
Uldum works fine as I tried it recently
Vashj'ir is alright I used (and I sitll) to level my characters here. Just search for the quests.
Twilight Highlands quest chain works fine (not 100% completed, but you can go really far)
Please take the quest at the big pannel in front of Grommash Hold if you are Horde and if you are Alliance well I don't know where that pannel is so maybe use wowhead or google.
Everything I said here has been personally tested by me.
The Quest there shall take me to Vas´hir dont works, The never coma a boat, and When I ride to Vas´hir and take the start quest, then the Quest with the fight where I shalll be capterede newer starts .
In Uldum shall I up on the Aliance Gunship an chapter a man, he fly under the ship And i vant camptere him :(
In Uldum I cant get the High Priest Quest with the fish, Every time I damage them They go on full life.
I remember all this quest, an do exacty what I shall, Think I will try a horde char, the server are maby fixed on the horde side, most people play horde as I understand :) Hope I works when I play a horde Mage instead :)