I totally understand your viewpoint of why pay $600 more a room that you are only going to sleep in? So if that's the truth, you plan on not being at your resort much at all, I'd go with the moderates. However, if you are considering that you may want to spend more time at the resort than just sleeping (swimming, eating, break time in the room, etc), I'd go with the deluxe. IMHO the deluxe resorts have better pools, eating options, rooms, transporation, etc. I mean they have to b/c they're more expensive! So your choice really depends on which type of traveler you plan on being: 1) away from the resort all day or 2) some time at the resort to hang out.
We had this dilemma this year when we were deciding where to stay (3 adult women). We eventually decided to do a split stay between POP (7 nights) and AKL (2 nights). We love the parks and usually stay all day. So while we're at POP, we're going to be doing mostly park days. However, we also love swimming and having hang-out time at a nice resort, so that's what we'll end our trip with at the AKL. Not that POP isn't a nice resort, we'd just rather have more time at the AKL if we're going to be swimming/eating/relaxing.