I am not sure how you guys are calculating AP values, but here is a breakdown of the three parks. For comparison sake, I did the Sea World/Busch Gardens ticket.
Lets start with Seasonal (Sea World doesn't really have one so they are not in this category):
Disney is $339.74 which comes to 84.94 per park
Universal is $186.37 which comes to 93.19 per park
Now regular passes:
Disney is $516.53 which comes to $129.13 per park
Universal is $260.92 which comes to $130.46 per park
Sea World is $188.74 which comes to $94.37 per park
So if you want to go by the number of parks (which in turn goes to the number of rides) Sea World/Busch Gardens is your best value, then Disney, then Universal. Is Universal giving you more NEW rides? No question about it. They are doing the most to their parks the fastest. But if you want more variety of things to do then Disney is really giving you the best value. If you want better Holiday events/shows then Sea World is going to be your best value. So really it depends on what you are looking for when you talk about value. But when you break it down by the number of parks the pass allows you to enter, Universal is not a good value at all.