Talents received a massive overhaul between Wrath and Cataclysm, one that saw a vast majority of talents culled and the trees themselves shortened considerably. It took a little time to get used to the changes, but in the end, the changing of talents wasn't really as huge a deal as I thought it'd be. Choosing talents on a character is still just as easy as it used to be. Don't worry so much about what you pick while you're leveling, and when you reach 85, you'll find plenty of sites online that will tell you the best stuff to grab at max level and why.
Which is sort of the problem, isn't it?