^To paraphrase Cera: maybe it would, maybe it wouldn't. I just like Ducky the way she is, such a lovely and caring creature. But I also would like to see Petrie doing the exact thing you said, if only once every few movies. Make the exchange of feelings more equal, so to say. Now, would it fit into 4? By the time of 4 the main characters' traits have been well established, so the authors had the opportunity, perhaps for the first time, to have a character significantly depart from his usual behaviour (Spike talking) and make the viewer notice it immediately. So, Petrie comforting Ducky wouldn't be out of place in the film either. But I still wouldn't like such a "Petrie moment" just yet. Maybe in a latter film. It's just my gut feeling.