According to @claiborneart's chart, I'd call myself a structure neutral, ingredient rebel on this subject.
But as a side note, I don't think a burrito is a good example of "ingredient neutral". Maybe beans and sour cream are a little unorthodox for "classic sandwich toppings", but most other common burrito fillings (beef/chicken, cheese, lettuce, tomato, even guacamole) are also commonly found in sandwiches. =/