Heya!

I like the idea to have every playerbase to play the style they want, but for now I think this is completely antiproductive.
Doing that now or after the PS3 release would mean:

- Changing typology of the server, constraining the players to go away from it and changing it (thanks to a free character transfer);

- If players get away from the server, the Linkshell in that server will be unbalanced, if not extinct or redone;

- The playerbases will be even more alienated each other;

- Some servers will have even fewer population, leaving any choice at the player but to play in a good-populated server where he doesn't like the playstyle.

And so on, and so forth.
I don't think this is a problem anyway. If people want to play what they consider FFXIV they should post more suggestions about how they think about the game in the forums.
The Battle system is getting a revamp, so who likes it now may not like it in the future.
If there's gonna be a PvP it will be some kind of Arena. I can't see a free-roaming PvP in FFXIV.
If you don't like the aggro indicator, just disable it.

In conclusion, I think this is not an argument to be discussed right now, as the game is still under development and the elements needed in order to justify this option are really few.

See ya!