It makes perfect sense that Luke would flounder a bit, since he's completely on his own as a Jedi and doesn't really know what he's supposed to do next, either for himself or knowing how to train anyone else. His own training was rather fragmented and cut short, after all.
Leia manages to single-handedly convince an entire race to abandon their allegiance to the Empire, which proves to be the most important element of the entire story in the end. The same race that had been trying to kidnap her and her children, mind. Not bad for pregnant and in peril, I'd say.
And who can forget the awesomeness of Mara Jade?