As I understand it rather than having many servers, TESO has one, well, mega server. Players are then put into different worlds(instances) This fixes low populated serers, overpopulated servers etc, but personally as a player I see more downsides than upsides.
Because there is only one server there won't be a PVP server, PVE server, RP server etc Because of this there won't be open world PVP and trying to RP on a normal server probably won't be a great experience.
Apparantly because of the big megaservers, normal auction houses won't work and thus we have guild trading, which is obviously terrible compared to the real thing.
So basically, what makes the mega server so great? Because I'm not seeing it.