Size matters not.How big is a DDI character PDF anyway? And that is the largest the file can be. As data in a database, a character would be trivially small.
A long, long, long time ago, I played EverQuest. We were limited to 8 characters per server. Those who paid a premium were allowed 10. When friends wanted to try out the game, it was easy enough log into a different server and let them have at it. But when a new race or class was added to the game, an old character had to go if you wanted to play something new on the same server with your friends.
Hopefully, WotC won't pull some nonsense like this. It just popped into my head when I was thinking about them storing my characters.
The CB sold me on the game, I don't want to go back to pencil and paper. Having everything from all the resources (books, Dragon, Dungeon, etc.) in one spot and with all the errata spoiled me. I tend to support the things I like. I was a yearly subscriber. I own most of the books and quite a few of the minis.
I can't imagine going back to pencil and paper and building a character with feats, powers, magic items, etc., from multiple sources. I have no problems with the math, its having a sword from AV2, armor from AV1, feats and powers from PHB1, MP1, MP2, HotFL, and Dragon - and then trying to reference this stuff when a question comes up. I love the CB, but I don't want the thing to be online only. So it's either restriced access to the CB, or restricting myself to a few sources when character building the old school way.
I too will have to vote with my pocketbook. My account won't auto-renew, and if there's no offline CB when my subscription runs out, then I'm done.