I think it would be cool if all starterzones has their own beginner dungeon with a max level heroic mode. I got this idea for a while and i think it could be cool if there is a little twist added to it as well. Let me explain
In every starterzone will be a dungeon for starters in a levelrange from lvl 15 to 25/30. Also these dungeon are available as heroic mode dungeons. These dungeon (normal or heroic) are only available for the faction's territory (horde or alliance) the dungeon is in. But every week one of those dungeons become available for the other faction as well (except Worgen and Goblin dungeons), but you cannot queue for these dungeons in the Dungeon Finder. You have to go to it in the real world with a party like the good old days.
Alliance
Elwynn Forest (Humans):
Stockades will be transformed for this feature.
Dun Morogh (Dwarves + Gnomes):
An opening has been found in the lake of Forlorn Cavern in Ironforge. You have to swim underwater to locate the entrance. It leads to an abandoned dwarventunnelsystem. Now it is home of many troggs. A part of the dungeon is crystalized like deepholm.
Teldrassil (Night Elves):
A tree has falled down southeast of Darnassus and cracked up an opening to an underground tunnelsystem loaded with corrupted servants, animals and everything. The tunnels leads to the small lake (check teldrassil map to see) for the final fight.
Azuremyst Isle (Draenei):
Stillpine Hold is bigger than always was expected. The Kurken (core hound) was just a distraction and guard of something bigger. The Furbolg of Stillpine Hold have something stronger to protect themselves in the back of their hold.
Gilneas (Worgen) (Alliance only)
Gilneas city is under attack. You have to defend the invaders.
The Horde
Durotar (Orcs and Trolls):
Ragefire Chasm will be transformed for this.
Tirisfal Glades (Undead):
An old catacomb with crypts of former Lordaeron Kings and Queens were found southwest of the Magic Quarter right under the throne room. Badly enough the bodies of those former royals does not rest in peace anymore, but the zombies and ghouls crawls through the corridors of the catacombs searching for flesh to still their hunger.
Mulgore (Tauren):
The Venture Co. mine is big enough to transform it (partly) into a dungeon. Most is still unused these days so this a change to use it. Well everyone knows what the Venture Co. wants. Resources, resources and even more resources. All to get the best profit to be rich. The altered nature badly when they found ancient stone elementals. They needs to be stopped.
Eversong Forest (Blood Elves):
When Arthas and his Scourge ravaged through Silvermoon leaving the Dead Scar behind, not all undead left this horrible path that splitted the city in two. Enter the space between Silvermoon and Ruins of Silvermoon to wipe out the last existing undead there.
Azshara (Goblins) (Horde only)
No Kezan or Lost Isles, because you cannot travel to there. So Azshara is the place for a Goblin dungeon. Gallywix is kinda greedy. He want all gold for himself. You have to infiltrate his Pleasure Palace on top the hill and play Robin tha Hood and bring the gold back to poor goblins.
Esspecially the heroic dungeons are worth to do as they drop rare and epic gear and weapons to use you cannot get anywhere else. Beating a dungeon also rewards rep tokens of the counterparts faction of it (Beating stockades rewards orgrimmar rep). With these rep tokens you can buy factioned themes epic gear for use with transmogrification, the argent tournament mounts and pets and more stuff.
THis is basicly the idea. I hope you like it.