While I love POR, I think I would mostly go with a value resort at this point. When we visit WDW, using our DVC points, we try to tack on a few week-end nights to extend our visit. Since those nights are so expensive pointwise, we stay at a value resort. My dd, 11, just loves the AllStars. Yes, she likes the slides at the more expensive resorts but she also likes the idea of more character meals too!!!
As far as the noise and room size go...the rooms at the moderates are not that much bigger than the values. I really didn't notice a huge difference. And the walls being thinner? I can't say for sure about that, but I can say that our stay at AllStarMusic, even during PopWarner time, was the quietest stay we have had to date. And it was much quieter than our stay at the Polynesian!! If you ask for a room on the back side of the resort you won't get very much noise.
So, if you think you will want a sit-down restaurant, a slide, more adult theming...then go with a moderate. Otherwise, go with a value resort. We found that we never used, well we did just once, the sit-down restaurant at POR. We usually ate bigger meals in the parks and just used the food courts for lighter meals.