Actually, reading the message boards about Everquest, Diablo II and the like CAN give you information on these issues (the whole TCP vs. UDP debate, for example). Funcom had the 'It Won't Happen to Us' mentality.
Let see, every MMORPG has had the same problem: server capacity and lag. Apparently, Funcom knew of this even through their 'final beta' (though I consider the retail product the final beta in this case). Solution: stress test the game with 3-4 times the amount of expected traffic, for days.
Hell, if game companies can't afford to test, they shouldn't be in business.