Not only would it likely mean no access to any possible future perks as you might see if DVC had VIP plans, as Chuck pointed out, it'd almost certainly mean the end of any such perks that were not contractual because it would be impossible to guarantee such perks going forward.
You are entitled to the info that DVCMC spends but not anything else including the resort budgets or DVC and this includes exchange contracts. Often you must present yourself in person with an appointment to get much of the info. I'm not very knowledgeable about how ME is paid but my recollection is there was a % of the expense that was passed on to resort management including in the transportation realm but not all, that it was essentially a shared expense. Hopefully someone knows for sure and can be more specific about this exact issue.
IF you've been a member 16 years, there were no DVC resorts with valet parking when you joined. This didn't come along until 1996 with BWV. At the time ALL valet parking at Disney resorts was free if I understand correctly, this changed for every one else where they had to pay some time ago. Also, the full cleaning on points was the same other than the relative timing for a stay 8 nights or longer.
Certainly there have been changes. No more special check in desk for members, no more cloth colored napkins, print shower curtains, etc. None of these are really material issues but more emotional ones, IMO. While there have ben changes, the basics are still really the same, home resort priority, banking options (minor variations), etc. You should expect PH to become more and more restricted and to eventually be eliminated.