I say "we'll see" for something that I may be willing to do/let them do, but I'm not willing to commit to until the time comes. For example, if the kids ask if they can watch a movie after we're done with schoolwork. I'm not going to say "yes," because it's hard to say exactly how long schoolwork will take and whether we'll have time before soccer practice, or whatever. I don't want to say "no," though, because maybe we *will* have time. So I'll usually say, "we'll see," and sometimes explain what it's contingent on, "it depends on whether there's time before soccer practice, and whether your room is clean," or what not. For me, "we'll see" means "I am not going to say yes if it turns out that it's difficult/impossible to give you what you're asking for, but I simply don't know at this point whether it will be possible or not." So I think there can be legit uses for it, although I'll agree that if it *always* means "no, but I don't want to give you a straight answer," then it's definitely a problem.