I know it's been posted back in July that they wanted to do this but didn't plan for it any time soon, but i really was curious on how you guys felt about this.
Account Achievements were planned to be launched with Wrath and clearly that hasn't happened. Account achievements would lessen the feeling of characters beings "alts" where you are discouraged to play because they lack that latest achievement or because you don't have your new mount.
I was hoping that Blizzard would soon announce account wide achievements especially since it would probably make me think of switching my main.
Source: http://www.wowwiki.com/Account_achievements
Thanks for your time.