Above all, the nickel & diming is exhausting. Not
DVC specific, but it permeates the entire time we're there (visited this Feb & Apr).
G+ is not DVC specific, but it kind of is. We bought in thinking we'd get APs and have not-so-frenetic days on vacation. Pre-scheduling 3 Fastpasses a day was awesome. Now we have to pay $60/day to play roulette at 7AM, or get the whole family up earlier to rope drop if we want to do our favorites. Then spend the whole day on our phones. None of that is fun/relaxing. We bought DVC with a certain way of visiting in mind, and we can't do that anymore.
For DVC-specific things, the lack of APs is insane. If I hadn't bought ours when they were available last fall, I'd be selling our points right now. I don't much care if it's officially DVC's fault or not; members need access to APs. But then, TWDC is on record stating their guest mix is more profitable now.
And some might think its minor, but the lack of Top of the World Lounge is maddening. On our first DVC visit my wife and I took in fireworks from up there, and decided we needed more points (which we bought upon returning home). It was such a relaxing place to be. It still hasn't opened, even though it takes minimal manpower to staff it.
We just don't feel like DVC is a priority for the company, and I'd actively caution anybody from jumping in right now.