I agree with the previous poster...
I would definitely say Blizzard Beach. They have more things, it seems, that kids (of all ages) can do.
The wave pool at Typhoon Lagoon really scares me, too. DH and I were there when I was pregnant and the waves (in an area where the water was only about three feet deep) literally knocked me over. Needless to say, I didn't go back in the wave pool for the rest of the day (which is really disappointing as that is usually my favorite part of the water parks!).