Well it's finally happened -- as of next month, you'll be required to have a Battle.net login to get into the game, so you might as well head over and merge your account up right now. It's not like we have a choice in the matter any more, but that doesn't mean lots of players still have apprehensions about the process. Naissa puts some of the concerns together clearly over on her blog -- putting all of her accounts under one username scares her, and that's a legit point. Not only can Blizzard presumably cut access to all of their games for just one (or even one false positive) ToS violation, but presumably, one hacker could now gain access to all of your Blizzard games with one hack. The online profile is another concern -- Bungie already has something like this running with Halo, and from my online profile, you can see clearly just how bad I am. With the Armory, there's a level of anonymity (you can't see your account name, just character names), but if Blizzard starts posting profiles under account names -- or even worse, "Real IDs," which are apparently real names -- that's one more layer of separation lost. Surely, they'll have to have a way to opt out of that.
Of course, the changeover isn't all bad.
Naissa says cross-game communication doesn't interest her, but in my experience (with Steam and Xbox Live), seeing what your friends are doing across games is a big help, and even people who say they won't use it might change their minds when they see what it can do for them. Cross-game chat also includes cross-server chat, and that should be a nice bonus as well. She also says that logging in to multiple accounts will be a pain, but Blizzard's already thought of that -- even if you have multiple accounts under one email address, you'll just get a selection screen. Hackers will presumably need passwords for each as well.
And as Blizzard has told us in the past, they'll have some meta-game stuff built into the Battle.net system as well, including decals, cross-game achievements, and a profile system where you'll be able (optional, I'm sure) to find out more about the people you play with. There are certainly concerns about the change, and Blizzard will have to do their best to answer them, but I think we'll see the benefits of this mandatory changeover when Blizzard reveals the system at large.