When people plan their trips take a look at the menus before going. If you pick places based primarily on what Mom and Dad want to eat it probably isn't fair to make a huge stink about the kids meals. If having the right selection for your kids is really important, than have a top 3 list in the parks so that you know which places are going to suit your family. I'll admit that my 3rd choice one night will never be a choice again, but at least I got us something and had a plan when #1 was closed and #2 was on the other side of the park.
We are a vegetarian family, so we really had limited choices for kids meals. We did a few things that worked for us to feed our 5yo:
Shared - he loves pizza, so I got a pizza combo meal, ate the side salad and he pretty much devoured the pizza. There was plenty for both of us. We could have also sought out the 3 pizza park restaurants that don't have kids menus and he could have gotten his own (we had pizza at our resort).
Eat at the resort - We stayed at CBR and ate several CS meals there, better choices at the resort then in the parks, I think the grab and go section really helps. We did share an adult breakfast platter, but could have gotten him his own platter of the exact same food. It just would have gone to waste though as the adult platter was more than I could finish off and turned out to be more than we could finish off.
Let them pick - I was shocked at how excited he was at seeing the Uncrustables

the thought of them turns my stomach even now. Boy o boy he ate them twice during our stay with a big grin on his face and we got one to take with us and he was asking for it when he landed! I never would have guessed so your kids may surprise you with their tastes and preferences.

Disney may know more than we think.
Use snack credits - We could have used snack credits to add fries or other items to beef up his meals, with sharing we never needed to do this; you can get a bottled drink or snack type dessert with your CS meal, so that can make up for the used snack credit. At breakfast you can get two bottled drinks with an adult meal. Our second was usually water to carry to the park.
For TS its a bit more rigid you'll end up picking some combination of the items offered. However, a number of them offer steak, fish, etc. not just the pasta dishes. He chose Mickey pasta at dinner and cheese pizza at our lunch. We used buffets for our other TS meals. As vegetarians buffets offer us the best range of choices vs the one and done of the plate menus.
Sure Disney can always make improvements. With the DP I think you can tailor things to make it work for you. Planning and having the info before you're tired, hot and hungry is helpful. It saved me at least twice and my family ate well at Disney and our little one never had an "episode" because he was just plain hungry. We bought him one OOP meal at McDonald's in DTD. He didn't eat well at Chef Mickey's (too excited by the entertainment

), so a couple of hours later he was hungry. He devoured the meal, so it was money well spent. I wouldn't have even bothered to try to find something at Earl of Sandwich for him. That night I got hungry after Spectro and remembered DIS comments about Main St Bakery. It ended up being an awesome stop for us. But again, w/o the education from DIS I'm not sure I would have even thought to stop in there.