But this will never happen.
(legal issues)
It will, when SDK will be released, in a bit different form than you imagine real p2p. Want example? Look at any better OTS (Open Tibia Server).
It looks like that you must "donate" to get better, unique items (in FOnline it can be PA or something worth much and not able to get in other way).
I am 100% that in future at least 1/4 servers will have system like that.
Anyway, back to the topic.
4th tag skill wont solve nothing because it will just allow alts to be more universal and will eventually just decrease amount of them. The only way to delete annoying alting is to make a blockade for IP or hard-ware ID it means on 1 computer there could be only one account, can eventually be done many characters for each account but impossible to login on both in same time.