New patches don't really excite me, and I play WoW every day. SW:TOR release day will be a big event for me; a new patch for WoW will be "oh, new patch, neat" on the day it's released. There's only so many times they can increase the numbers on items before you stop considering it a big thing, and excluding all these new numbers, there's rarely ever that much in even the bigger patches. One or two dungeons really isn't a lot when you consider the size of the game - the longevity is only in the difficulty of the content (ie repeatedly trying to beat certain bosses).
Then again I'm not a hardcore raider who considers the aim of the game to be to "get through the content". I haven't even done most of the original Cataclysm raid bosses yet, and I don't feel I've had an inferior experience of the game to someone whose guild is farming Ragnaros heroic.
Even if WoW released an expansion that added an amount of new content equal to every single thing they've released thus far, I wouldn't be as excited for it as I am for SW:TOR (or GW2). A completely new gameworld to explore that isn't generic fantasy or low-budget production is a rarity these days, even with the massive number of new MMOs released each year, and I genuinely do believe that these two games will provide us with the most immersive MMO worlds since Azeroth.