Adam, I'm not sure there is a standard, but I can testify that my wife doesn't care for bruschetta because, well-made, it starts with a chewy rustic Euro-bread and then grills (or toasts) it so as to make a firm base for the tomatoes and other topping. Depending on one's taste, this can be either "interesting" or "really hard to chew."
Good question, though! Since Mary doesn't like it, we don't order it too often, so I'll be interested to hear other opinions as well.