I love Worf, though he's not my favorite DS9 character. If nothing else, it seems Terry Farrell was able to really bring out some personality in Jadzia when Worf came along. So I'm definitely glad he joined the cast. I also enjoyed his interactions with Sisko. Plus, for me there's something about having Worf that adds a realness to the whole show, although I'm sure that doesn't make sense to everyone. It's a personal thing I can't really explain.