Disney has offered different dining plans for years and they were always a bad deal (IMO). So when they changed to the current DDP, I guess there was reason to be optimistic. Making most people pay full price for the rooms in order to buy the plan certainly helped Disney in one area.
Personally I'm a little surprised that they are making such radical changes all at once (if the rumors are true, of course.) Seems like they would have made the changes less noticable if they had simply lowered the price and eliminated the tip this year, and then looked at removing the appetizer next year.
DDP or no DDP, I don't think there will be a huge impact on popular places like Chef Mickey's or Le Cellier. I'm of the obsessive "book my reservations at 180 days" type, out of fear that restaurants would fill-up. I've heard many claim that the issue of availability at MOST places is blown way out of proportion and that even with the DDP you can still call the same week (or same day) and still get a seating most days. Don't know from personal experience, though.
I think we're more in danger of losing the CS locations at AK. Between Tusker, Yak and Yeti and Rainforest, AK will soon have three table service locations. Unless Rainforest and Yak both opt-out of DDE, I could see Disney removing Flame Tree, Pizzafari and Restaurantosaurus.
But maybe Rainforest and Yak will both opt-out. They are independently owned so they have no obligation to participate.