So as a side remark from some dev panel at Blizzcon it appears that we will get cross-server dungeons, complete with a cross-server looking for group system in patch 3.3. Which is a nice idea, because the larger the total pool of people is from which you can recruit for a group, the higher is the probability that the group will actually happen. And while players are always tempted to shout their LFG requests in trade chat instead of using the LFG system, they can't do that cross-server, so the underutilized WoW LFG system might see some more use.
Now Ixobelle points out correctly that a larger pool of players doesn't help all that much if all of them are dps. Quote: "The issue is that no one wants to fill roles that require anything resembling responsibility. I'm not going to qualify that 'responsibility' statement, as it's ground I've covered before. People want to DPS because it's easy (not simple, just non-commital). There will now be 700 little sword icons in LFG, but the lack of little PLUS or SHIELD icons will stay the same. Multiply any large number by zero and the result is still zero."
I think Ixobelle got the effect right, but not necessarily the cause. That is especially easy to show for the leveling part of the game. Why is it hard to find a tank or healer for Blackfathom Deeps? Because nobody in his right mind levels with a tank or healing spec! I did it with my first characters, my warrior and priest, but that was in the context of a guild environment with frequent grouping. The new characters I play now, the druid and the paladin, they level with a dps spec. Grouping during leveling is such a rare occurrence, and having a tank or healing spec is such a penalty to solo leveling speed, that it takes a special sort of masochist to level as tank or healer nowadays. And at the level cap the situation changes only for those who group or raid often. A casual player who spends his time doing daily quests, PvP, and the like, and groups rarely, still will favor a dps spec because it is simply so much better for his purposes.
But there is a bright side: Cross-server LFG will increase the probability of grouping during leveling, which will increase the interest in a tank or healing spec. With gold being so easy to come by nowadays, respec costs have become cheap, and at level 40 you can have dual spec. It doesn't take a rocket scientist to figure out that in a LFG system with "700 little sword icons" you'd better respec to tank or healer when you want to go to a dungeon. So it is quite possible that things won't be quite as bad as Ixobelle fears.
A reader wrote me about cross-server LFG, observing that this system will help World of Warcraft when server populations decrease. That is certainly correct. I wouldn't go as far as to say that Blizzard is introducing it because they foresee a decline, but with activity numbers already dipping between expansions and during summer holidays, any system that alleviates the problems of declining server populations is welcome.