We looked at this; for two people in a Deluxe resort, the AP room discount is better than the free dining plan, because they both are worth $70 pre-tax dollars, but you have to buy one-day tickets, too. For three or more people, the dining plan trumps the room discount.
For all other categories, the dining plan is a better deal for two or more people---it's spectacularly better in the Values.
When the AP discount was announced, we thought about a standard AKL room. But, our four night/three day trip is $450 less expensive in a Value room with free dining (plus we get four dining plan days to use over three days) and that was too good of a deal to pass up so we actually downgraded.