That, and Q's comments about her. I wonder if some of the writers had some ideas for Guinan that never panned out.
Yeah, I kind of think that's what happened. Q says something about her like, "this is a dangerous creature, you have no idea." And the fact that it looks she's going to fight Q in that episode seems to imply that their equals on some level... is Guinan a Q-like being, is that wht they're saying? And yet, when we learn more about the El-Aurians (I think that's what she is), all we get is that they're "a race of listeners," very persuasive people who put other at ease and can get them to do stuff. Interesting, but not exactly Q-level power. I think they hinted at some things about Guinan that never came to fruition.