The same agent who said "Male point of view doesn't sell" also refuses to consider novels that have multiple points of view. Oh well, I'm guessing Roberto Bolaño probably never considered submitting The Savage Detectives to this individual anyway...
My gut response is to say, "If it doesn't have multiple points of view, it isn't really a novel."
Then again, having several viewpoint characters does lead to technical problems. I've read Anna Karenina a lot of times, for example, and sometimes I get all the way through without wishing one of the Levin sections shorter, so that I can get on to the next Anna Karenina section -- but other times I don't. If even Tolstoy couldn't entirely avoid the risk of having one character become more interesting to the reader than another, perhaps this problem is unsolvable?
Having worked on a lot of (unpublished) novels, I notice a trend in my own work toward fewer and fewer viewpoint characters per novel. Does this reflect a craven bowing to commercial pressure on my part? A tempting alternative is to view it as a sign of my own increasing psychological integration. When a novel has two viewpoint characters, these tend to reflect warring elements of the author's psyche, but there's something satisfying about forcing these conflicting elements into a single character... This is a topic I may return to.