I wouldn't miss the Dining Plan itself. I have used it and liked it, but prefer the Disney Dining Experience for the flexibility it provides. I would miss the possibility of the occasional Free Dining Plan that has been offered, I'm prepared to accept less flexibility for free food
I think the biggest problem the DDP has is the impact it's had on availability. I don't mind deciding six months in advance where I'd like to eat, but there are plenty who do. With the advent of DDP, spontaneous dining at TS restaurants virtually ceased to exist, alienating spontaneous guests and locals who don't need to make long range reservations for vacations to the World...
I know it was an almost constant when we were there in February to see people being turned away because of not having ADRs or being told to come back in two hours, there might be something. "Veteran" guests who know what to expect can plan ahead, but a novice who booked a vacation to the World without doing any real research and paid for DDP might be justifiably bitter if they can't actually use all [or potentially
any] of their TS credits. I would bet Guest Relations received "an earful" from a number of guests.