It was reported a while ago that 70% of WoW trial players never make it to level 10. There are a couple of interesting observations you can make about this statistic, and some important inferences to be made as well. First and most obviously, WoW is losing an enormous chunk of their potential customer base. Second, players are losing interest so fast that they aren't even willing to play for free.
Perhaps one of the important questions to ask is, why use level 10 as the benchmark? It may be the case that 99% of trial players make it to level 9 and quit, but its far more likely that this was chosen because its when Talents become available, and when many classes gain a key ability that defines their class. In other words, level 10 is when "the good stuff" starts. Its also the very first opportunity for a player to make their character different from all the other new characters of that class and race. If you're hiding the fun and player identity behind hours of initial grind, what would you expect to happen?
Cataclysm sounds like a brilliant idea, one which will revamp the starting areas and bring veterans back into old Azeroth, giving the current playerbase a great reason to invest more time and keep paying those subs. But for a brand new player the visuals and quests will be taken for granted, and if the initial grind-to-fun and grind-to-identity of 1-10 is still there, WoW will still let a huge amount of potential subs slip through their fingers.
Cataclysm should change the starting point for talents (and key abilities) to five, right around the time players are finishing the initial cave quests and leaving the very first area of the starting zones. Any sooner and they would be overwhelmed by too many features (there is a learning curve, small as it may be). At level five there should be a quick tutorial explaining the classes different talent trees, with a brief overview of each. This way the player will be less than two hours into the game and will already have their "cool abilities" and at least the beginnings of a sense of uniqueness in a 10 class world. Come to think of it, veteran players are so used to spending a talent point immediately after they level up, they're probably Pavloved into opening their talent menus, which will lead to exactly 9 instances per character of "…oh right, I don't get to do that yet. *sniffle*". Cataclysm is supposed to reinvigorate the current playerbase, so why not surprise them with talent points earlier?