It's been on my mind for a long time how to make WoW more refreshing regarding storytelling for your character.
Now, I know Old Republic is lacking in more than one way, but one thing it did RIGHT was telling a story, where beside the normal quests, you have your class quests, which can only be accessed through certain gateways by certain classes.
In WoW, this would be a very difficult thing to implement into already existing world, even with phasing,... or it would, until the Thunder King patch came, where you advanced your faction's war-effort on Isle of Thunder through single player scenario, or the "legendary" Warlock questline.
With that, we could easly put in characters that would serve as "start scenario" button and we wouldn't affaect or developers to be forced to change the zone.
Now people may start an argument that this will consume too much time developing story scenarios for all 11 classes every 10 lvls, developers could use for other things and we'd be back to problem #3 of Cataclysm, but I disagree. Pretty sure they have other people to handsle that.