Rift launches tomorrow, and has published a list of server names. Which promptly caused a discussion between some people preferring a single-server architecture like Guild Wars, EVE, or City of Heroes have, and others preferring strictly separate servers for a "better community".
I am torn on that issue. I never liked being in copy #57 of a city zone, and having to make sure that I'm in the same copy as the friend I want to meet. Single-server solutions without instances only work for space games with a huge universe, and even there you get some especially popular places with permanent lag problems. But the separate server model has problems as well: What if you find that you and a RL friend of yours are on different servers? But if you allow server transfers, many of the "better community" advantages go out of the window. And anything players queue up for, be it PvP instances or PvE dungeons, results in larget populations leading to lower queue times, which is why WoW has these set up for server clusters these days.
The worst disadvantage of having separate servers is that they don't deal well with shrinking populations. That used to be not an issue for the earlier games, where MMORPGs typically had a long growth period and a slow decline. But since WAR and AoC showed that the decline can be rapid and start as early as after the first free month, the multi-server model looks more and more like a risk. Shrinking populations mean either too many servers being underpopulated, or server mergers, which make for very bad press and suggest to the players that the game is dying.
Thus in the balance I think a single-server model with instances is probably the least bad solution. But I'm interested in hearing your opinion on that issue.