Yes, there are many people who visit WDW regularly as CRO resort, but
DVC members have basically committed to going multiple times a year for 30-50 years. Sure, the equivalant room "cost" may be relatively inexpensive, but I'd be willing to bet that DVC members are likely to spend more money at WDW over their lifetimes than guests who frequent the cash resorts. While DVC is a great deal for us, it's an even better deal for Disney. DVC provides Disney with a loyal and relatively stable pool of visitors, so yes, I would like to see more perks for DVC members, because frankly, the ones they have now are generally pretty lame.
But of course, DVC/Disney is a buisness, and the perks are all marketing driven. The perks were great over the first several years of DVC, but since it has taken off and people continue to buy in at record numbers, perks will just continue to dwindle away. And there certainly won't be any new significant new ones offered until it hits the skids (if that ever happens.)