simple way to prevent atl character storages

[MagicManICT]

The answer to your woes is this: Subscription fee per month/account with no option to make new char until the old one dies. I cant see anything else that could limit the ammounts of alts.

And sub games have never had people with 30 or 40 active subscriptions, right?

Nope, no way to actually solve this. You just make it harder and make people jump through hoops to accomplish the same thing which, in the end, just creates a bigger headache for the support team.