You have to remember when the retailers held the game developers purse strings. If the big retailers didn't carry the game it likely wouldn't move through in sales thanks to physical distribution. So the retailers started demanding exclusives. At first it was cool because it was X retailer got an exclusive so if you knew about it you got neat little thing and prompted "Where did you get that?" in big games. Now with digital distribution being a thing the exclusives are used as prods to encourage preorders. Some still try to have exclusive items in games or whatever...
Today if a company wanted to sell me something exclusive that would get me to pay a higher price for a game or even just pre order the game... give me MMO or MMOlight games with other players that are age group exclusive. (with some negligible way to verify age beyond a drop down box.) 30+, 18-29, and under 18 would be good broad categories I think.
I would pre order a half way decent game that did this JUST to encourage more people doing it. I have a feeling the weebs would focus on 18-29, many here would just go in the 30+ servers and be happy with it. And the fakers well they would be wherever.
To account for families if multiple accounts exist in an household let Parents invite their kids to play with them when they want to. No big thing it's just copying some data between databases and keeping it in sync. (or just using a bigger character DB that all servers use and well you get the idea.)
I get annoyed playing with the younger generations sometimes. Like if I were to play a looter shooter I would TOTALLY play on a 30+ server and not a under 18 server. Last thing I want is some twitch happy caffeine junkie kid ruining my enjoyment of the game with a mouth that simply can't stop saying bullshit.