I guess it somewhat or totally depends upon what type of food you are looking for...how much you want to spend..how important keeping your kid happy is.
My daughter is now 6, but since we live here, we have been going to "kid friendly " for awhile.
Burger Joints....Red Robin in University City, Ruby's Diner (although I personally don't enjoy their food), Corvette Diner (the waitresses are supposed to act attititude rude, throw straws and bubble gum at you, so quite the hit...but located in Hillcrest..kind of gritty around the outskirts, also the center of the city's gay community...killer Elvis shake!)
Old Town has Rockin' Baja Lobster, one of my fav's since you get seafood in bucket, but unless your child is a corn'dog eater...might not work. I am sure there are other things on the kid menu...but my daughter eats mostly the rice and beans!!
Dave and Busters....I hate it..LOUD, but a common kid destination.
Rubio's fast Mexican...yummy, kid's meal has a churro and a toy.
Drawing a blank otherwise, but ask more and I will check back.