As far as Jake goes, I can't understand people liking him or disliking him one way or the other. He's just there. I have no opinion of him.
I really can't understand that either. He was a good enough minor character that just got more and more phased out of the show as it went on. I thought he had some good moments with Nog and when the Cardassians took over the station, but he was far from being really important, and became more of a recurring character than a regular.