We bought into
DVC in 2006 and still love it. Every time I get annoyed at a perk or process change and think about going back to Disney as a resort guest, I run the numbers and DVC remains a good deal for me and my family.
Having said that, there have been a LOT of really basic changes to DVC in the 3 years I've owned...some are perks, some are processes.
The dining plan is nowhere near as good as it was originally--but remains better (for my family) than not using it. I'll miss the AP discount when they take it away (and I'll bet you a hot fudge sundae they will!). I don't ever have a car at Disney, and if I did, I'd almost certainly not valet park it--but I understand the unhappiness of the people who did make use of that perk.
For me, the most upsetting change was the waitlist rules. The new rules really hurt my family. My son can't (won't?) commit to most of our Disney trips months in advance--when we first bought in he was a college student; now he's a law student...he simply doesn't know months in advance that he can/will want to go...but I desperately want any Disney trips he winds up able/willing to take...it used to be that between being flexible and day-by-day waitlists I could piece together last-minute vacations, even during busy times like spring break. No more. It may be that the new limit of two wait lists, that cannot be day-by-day, and must accommodate booking categories, work for most DVC members, but it doesn't work for us. That was a real loss to me and my family. Having to give up those last minute (generally 8-6 weeks out) opportunities to go to Disney w/my son hurts.
So, for me--the problem isn't any one perk or process changing, it's that the "parade of changes" is fairly constant. I've come to the conclusion that you really cannot count on Disney/DVC for anything beyond the villa that they promise in the POS. If you know that walking in (I did, but didn't really realize it) you may be fine.
I still love Disney and I still love experiencing Disney via DVC...but I don't like the constant pace of rules and perks changes. In other words, I like DVC a lot less now than I did when I first bought in...but still like it enough that I'm not planning to sell any time soon. But I like it enough less that I've decided to not add on (again), and as a result will skip a trip I would have taken under the old rules.
I do think the issue is "expectations." So much of the appeal that caused me to buy has changed or gone away.
On the other hand, I need to be fair: when I bought in, I had to pay $9.95/day for internet access (an absolute must for me; ability to work via computer is what lets me go!)...now, I don't have to pay that fee. That was huge positive change. Almost makes up for my new inability to piece together last-minute trips.
Good luck w/your decision.