Looking at the price for a suite at Art of Animation next summer, the price is pretty much the same as the Polynesian, and just a bit less than the Grand Floridian. I know it's a "suite", but at 520 sq ft, it's just a bit bigger than a standard room at the Polynesian. What would you do? BTW, there are 2 adults, 3 kids.
I know there aren't many discounts for AoA available to the general public right now, but at this point we don't know for sure what the discounts might be for either resort next summer (I'm assuming you mean summer of 2013).
Of course, it's possible that the prices of Poly, once discounted, will be even lower than AoA.
My gut feeling about this choice - the biggest perks for staying in AoA will be a little more privacy for whoever gets the master bedroom and an extra bathroom, and whatever comfort you may get for being in a relatively new resort.
The perks for Poly will be location, monorail access to MK and Epcot, more onsite amenities, 2 sitdown restaurants onsite, and by being on the monorail, quick access to the restaurants and amenities of the other monorail resorts. Also, by having monorail access to the MK, you also have less of a hassle if you don't have your own car and want to go to other resorts.
I don't know what's more important for you, locking yourself off from the kids, or all the bells and whistles that comes with staying in a monorail resort.
I also know in the past you've rented DVC points. Quite frankly, unless you are averse to these resorts, I'd rent points for a 1BR in either BLT or VAK. In retrospect, I think you don't like to BLT - if memory serves, you're fine with the location and amenities but not all that keen on the design and decor, am I right? Can't recall if you've expressed an opinion about VAK. But staying in either of those resorts, I'd feel like you're getting the best advantages of Poly AND AoA combined. You're getting the amenities of deluxe resorts, and with the BLT you're getting a prime location with easier access to all the other resorts in the World, just like you would at the Poly. You're also getting a separate master bedroom and 2 bathrooms like AoA. Plus a full kitchen and an in-room washer and dryer. Unless there winds up being a free dining promotion at that time you want to take advantage of but can't if you rent DVC points, that's the way I'd go.
While you're at it, why not see if you can rent points for a stay at the Grand Californian? Someone can book that out for you 11 months in advance, and then you'd know whether or not you're getting in. And I'm sure you know this but just in case, there are "Premier" passes that gets you an annual pass at both WDW AND DL. If you were to rent points at VAK or BLT, and then points at VGC, and a Premium pass, it seems like that'd be a good way to go (again, unless super special promotions come out that supercede the savings you'd get renting points).