I think the other two have explained this well, but I do know that, in movies more than books, I am often really frustrated that members of a particular race are almost always bad guys. To use this example, for instance, if we looked at all movies recently that portray characters who are Middle Eastern, what percentage of those characters were bad guys or terrorists or whatever?
While it's not quite as common anymore, I remember being younger and criminals were almost always African-American. Or movies during the Cold War where bad guys were always Russian.
It actually does bother me because I feel like, when the vast majority of portrayals are negative, it is encouraging a general opinion that people of that race are more likely to have whatever the negative trait is and I feel it is incredibly unfair. I think it also goes pretty far in showing how average society sees these groups.
I guess my way of thinking is two-fold. Yes, lately many terrorists have been from the Middle East (though certainly not all), and so yes it might be more accurate to have a terrorist in a story also be, but why do people feel the need to write so many stories about bad guy terrorists in the first place? Second, why can't we see more characters of these various minority groups who aren't bad guys, but just normal people going about their lives? Why don't we see the neighbor down the road who helps rescue the MC and helps him find shelter be a Middle Eastern man? Or an African-American cop? Or the Hispanic woman is a teacher instead of the janitor?
I'm not really sure that I'm making sense. I just feel like there's no balance, and that the ratios we do see tend to encourage negative views that can be interpreted to imply that more people of a particular group fit into a category than really do. I mean, the vast, vast majority of people from the Middle East aren't terrorists, they're normal people living normal lives. I wish we could see that portrayed more often.
And none of this goes to the cliche issue at all, but seriously, if you are going to do it, why only bad guy Middle Eastern terrorists? Why not the IRA, or a homegrown American crazy person like the ones who did the Murrah Building? When something is done over and over and over again it just becomes cliche. I'd much rather find out that the bad guy was someone I hadn't seen be a bad guy in fifteen other movies (or books) before.
Anyway, I don't think audiences would typically rebel if we presented Middle Easterners as sensible. Hell, this audience member would be cheering it. Sure, there are some racist asshats out there who will have a problem with it, but that doesn't really matter. There are always people who won't like something for whatever reason.
I remember seeing a bit on the Daily Show awhile back discussing someone who had said we need a Muslim Cosby Show that could portray a Muslim family as a normal, everyday family in a relate-able way. I think if we had more "sensible" portrayals, as you put it, it would make it easier to get rid of those stereotypes.