We are thinking about the same thing. We did a mock menu to try and see what we would spend out of pocket versus the plan and it was about the same. The only reason we might stick with the plan is so that we don't act too cheap and ruin the vacation for the kids.
We're in the same boat. Half our family are vegetarians. There are quite a few options for sure, but I'm not sure the dining plan makes sense for vegetarians.
We have booked with a quick-serve plan. The kids are super excited about the artisanal milkshakes, but I can't seem to find any kids meals that would let you choose a fancy milkshake with their meal. I must be missing something.