Often people who love Mexican food but don't like San Angel are used to what I call Gringo Mex. Very Americanized Mexican style food. Also, most Mexican food in the USA is similar to the style found in the Mexican state of Sonora, tacos, burritos, chimichangas etc. Mexico has far more styles of food just as the USA does. San Angel tries to bring some of this to WDW. That said, we love San Angel.
This trip we will have a 12yr old girl with us. She is often a picky eater. She loves simple Mexican food such as quesadillas, tacos etc. But doesn't like anything spicy, too wild flavored, hates onions. Basically just likes rather plain with light seasoning and not much sauces, salsa etc. Being that I love Mexican fully loaded I'm unfamiliar with whether San Angel would have anything for her. Maybe order the steak without the sauce etc?