"I went to my first SF con looking for SF" sums things up nicely in some ways. I hate panels where people say the equivalent of "this has been talked about" because you know, not everyone has heard it.

Every now and then I hear people saying "Oh we've already done that panel three years ago," and that's fine, they might be bored with it, but there are new people who have come along since then.

I think a few more structured panels is a good thing - either having moderators, or a team of people you know work well together. There are people I would never appear on a serious panel with either because they will talk over the top of me because I'm too polite to cut in, or they will spend their time telling 'amusing' anecdotes, that are only vaguely related to the panel.