I was not planning on picking it up but it seemed that destiny had different plans. I had an active subscription even though I haven't played in months (got the year thing for free Diablo 3), it came out on payday, some of my friends came back to it, and the day after it came out I found myself with a day off in a hotel with free internet. It was too much. I broke down.
So far I am thoroughly impressed. Something about Cata just seemed off to me but Mists is very interesting and the music is especially fantastic. I am really enjoying the monk class and Pandaren starting area. My first few hours were some of the best gaming I've done all year. Good job, Blizzard.
I didn't get the expansion but I went back to try the latest pre expansion patch last night to see if it was worth it. Same as you I am on the year plan for the free diablo (sucker). Anyway I had the opposite experience to you, logged in to my old character which is still in my old guild, sorted my new talents and abilities out, started doing some quests and just logged of because it was utterly dull. I did create a new panda warrior before that but only lasted 5 levels before getting bored.
I still want to like WoW but I just don't have it in me anymore, I do hope you enjoy going back though and enjoy the expansion.