more seriously, having travelled much, and now living "abroad" i think it's way over-rated. people are fundamentally the same. the ways in which societies differ are in the rituals people are accustomed to - and dealing with that gets old quickly.
Two summers ago I participated in the Mongol Rally (http://www.theadventurists.com/the-adventures/mongol-rally). Getting to connect and hang out with locals along the way (particularly in Uzbekistan, Kazakhstan, Siberia, Mongolia, etc) was one of the highlights of the trip.
In addition, the fact people are "fundamentally the same" is actually something I derive a lot of pleasure from, given it continues to reinforce the base "good" that we all have in us (despite what the MSM might otherwise tell us).
maybe another way of making my point is that the kind of people whose mind is most likely to be be broadened by travel are already aware of the kind of issues you might think they would learn. while those so closed they don't get it, won't - travel or not... your argument only seems (to me) to apply to the lucky few who are closed-minded at home, but open-minded enough to suddenly change when the food is different or the people don't react the way they're used to.
I think that experience is the best teacher. Whether or not you think you understand issues, or think you are experienced enough to deal with certain situations, you don't know that until you are put in those situations or confronted with those issues.
I also think it's a mistake to say that people are binary "close minded at home" and "open minded" outside. People have a range of experiences and impressions that colors every interaction they have.
Living in a different one of those cultures can be very educational, but it's somewhat hard to break into unless you have some organic reason to be there or social connection. People are often resentful of "lifestyle tourism", the stereotypical one being an upper-middle-class white kid who moves to a poor minority neighborhood as a cultural experience. Small rural communities can also be quite closed as well, in terms of being able to really join the culture (vs. just visit the town).