As with other types of sandwiches, the bread is substantial part of the whole; it’s not going to be a good sandwich without pretty good bread, at least.
There are certainly exceptions to the curse of Mrs. Baird’s afflicting area Mexican eateries. The fairly new Urbe, from Hugo Ortega and team, has excellent breads for its torta-like creations and Mexico’s Deli on Dairy Ashford, still possibly Houston’s torta king, has long served quality rolls for its innumerable sandwiches. But, unfortunately, when thinking about a torta at a Mexican restaurant, you might want to think more about something else.
Lame, processed-tasting supermarket bolillos; the problem at many places.