An AP can, but won't always, save you money if you buy it just for AP resort rates. The availability of other discounts and package specials is a wild card. Let's look at an apples to apples comparison and see how you might save.
Let's assume you are going for 6 nights, you need 7 days admission, and you will visit Disney Quest once and a water park once. You buy an annual pass ($392.99) and the other two admissions ($33.02 each) for a total of $459.03. A 7 Day/6 Night Ultimaye Park Hopper would have cost $333.35 (advance purchase). You have spent $125.68 more on the annual pass. Keep in mind that only one person in the party has to have an AP to get the discount.
Now let's look at the hotel room. I'll use the Poly as an example as we are staying there with an AP rate. Rack rates for our dates is $299. Worst case you pay that.
AAA member? Maybe you get a 10% discount and pay $269.10. Let's assume there are no other discounts available and go with that. Our AP rate is $189. That is a savings of $80 per night. Multiply by 6 nights and the AP saved you $480 on the hotel. Subtract the extra $125 you spent on the AP and your net savings is $354. Compared to rack the savings would be $533.
The question becomes whether that is a bigger savings than you could get another way. Back when there were available room only discount codes this AP strategy might not have worked...........but those codes aren't out there now. The Fairytale package probably was a better deal...........but that was an extraordinary discount. Not sure what kind of savings the current Visa 'Kids Play Free' promotion might get you..........depends on how many kids you have.
So an AP can save you money overall if you buy it and get an AP resort rate. Then again, if other better promotions are offered or you miss the AP rate, it might not. Personally, I think the "buy the AP just for the resort discount" strategy is sketchy. Of course it is a no brainer if you can get two trips out of the pass, but for just one trip it is hit or miss.