OP, you've used the analogy of purchasing a higher-cost ticket to a ball game and how you get more perks from that. Not a valid analogy in my opinion. In this instance, you purchased a "real estate interest" in a resort (that's how they said it when I purchased). You get the perks that are associated with that. More space, deluxe resort amenities, location, etc.
You don't get any perks associated with the theme parks unless they're specified in your contract, or DVC decides to negotiate a deal with another arm of the WDW company to offer you something, based on their marketing needs. Those deals are transitory. You are currently (generously) offered a discount on an AP, but you're not paying more to access the theme parks than I am. If you were, I think you might have a valid argument as to why you were entitled to additional perks.
When I purchased DVC at BoardWalk in '99 there was no discount for park admission to DVC owners. So instead of saying that because they're now offering DVC owners a discount on APs somehow makes DVC responsible to offer even more in-park perks to owners, I think you should be glad of what you do get.
I remember hearing that people who purchased early, at OKW, got free park passes for a time. Not in my contract, so I don't get it.
When I purchased, we could pool hop everywhere...including Stormalong Bay. It was a nice perk to be able to walk over to the Yacht and Beach Club to use Stormalong Bay. Once Beach Club Villas were constructed that perk ended. Again, that wasn't in my contract, so I'm not entitled to it.
I remember similar discussions in the past on these boards related to this. "Oh, I think because we've made this commitment we should get more." Like others have already said - Why? They already have your money.
Fast Pass existed a long time before FP+. Even though Disney could have made it a tiered system based on resort level, they never did. I doubt they will now, nor do I think they should.