In the upcoming “Mists of Pandaria” expansion pack for World of WarCraft achievements will now count for all of your characters, as well as mounts, companion pets and titles. Theoretically they should cover each and every single character connected to your Battle.net account. I haven’t found solid evidence of this yet, but it will be rather daft if it only applied to separate licences.
This to me is a very good idea and has added a lot of fuel to the fires of speculation spreading around the Internet. We already have account-wide achievements in Diablo 3 and, to an extent, in StarCraft 2 (since you only have the one “character” in SC2 regardless of what you do).
My current speculations involve the evolution of Blizzard’s new Battle.net service. I can see it evolving into a similar service to Steam or Xbox Live, where you have a gamer profile showing all of the achievements you’ve earned in various games. It could use our BattleTags as the equivalent to Xbox Live Gamertags or Steam IDs.
For instance, my BattleTag is Ulbrecht#2965. My Battle.net profile could be displayed as a webpage at www.battle.net/profile/Ulbrecht/2965 (that page does not actually exist, I’m just using it as an example). My Battle.net profile will then show you which games I have played, how many achievements I have earned, the status of my World of WarCraft and Diablo 3 characters and so forth.
I can also see Battle.net becoming a desktop program, very similar to Steam and Origin, where you can download and launch games from one place and chat with your BattleTag and Real ID friends without actually needing to be logged into a game. Perhaps Blizzard will allow third-party publishers to develop and sell their games via Battle.net, something which was hinted at in a leaked image of a development timeline.
And maybe, just maybe, an option to “appear offline” will become available in future.
This is all just speculation, of course. But I find it rather exciting.