Another random idea...
"G" in-game throws down your banner at your cursor location. Instead of the Altar, they could just make the banner a mobile respec station when you right click on it, change your skills out and then after a 5-10 second cast time (To prevent in combat changes and also similiar to Stone of Recall), it'll complete the skill changes and you're on your way.
With that, you could respec on the go anywhere you like so long as you're out of combat.
Or they could just make it so you choose your skills in the skill pane, than have to hit an additional button such has "Change", it'll do the 10 second cast time and again, you're on your way.
Either way, both options eliminate the porting back to town, though I don't really mind the current Altar anyways, it's a moot point once you get the Stone of Recall. I don't really see how a 30 second run back to town to change skills will kill anyone but the seriously impatient.