Brennan is insanely hard to write for, unfortunately. She sees the world from sideways. And that's really hard to get into fic, dialog and otherwise. Booth is easy. Booth is every guy out there, in some ways. Though he's slowly sliding sideways, too.

Brennan doesn't believe in marriage! HAH! on those fangirls. Now, having a fling? Maybe now, she would. Except she's already stated that having interpersonal relationships of that nature between colleagues is bad.

I do think they should have the "we are drunk" sex, though. And then Booth can angst and Brennan will be "er, yeah. It was just sex." and give him puzzled looks.