Everyone was in full rue mode when the portals were removed from Dalaran and Shattrath. Having to level characters through those continents was more than slightly painful at this expense. So I've come up with a very simple solution to rectify player travel issues between these continents for a more streamlined, but not too give-away approach.
Rather than adding portals to the major cities in Dalaran and Shattrath-
Add portals to Dalaran and Shattrath in Stormwind and Orgrimmar.
They're already the intentionally new portal hubs. Players already camp SW and Org more than they ever camped Dal. There's plenty of space to squeeze in a portal to each of the cities, if not by the portal rings, then in the vicinity of the portals to the Blasted Lands.
This makes it easier for leveling players. It does not distract from the main hubs. And it will facilitate travel just enough for people to TRAVEL more rather than camp cities quite so much. I think it could be a nice balance between "grounded" and "go anywhere in WoW at the touch of a hearth".