I can't understand why Hathaway wouldn't be thinking about promotion or would want to leave the force if Lewis goes. Doesn't really make sense to me. I'm also puzzled as to why he doesn't have a girlfriend or any love interest. Its as if they have stopped developing Hathaway as a character.
I liked the fact that they never went too deeply into Hathaway's character - to begin with he was enigmatic and small clues to who he was were given away here and there, such as why he left the church and the possible abuse he'd suffered as a boy.
Also, the fact that he was so reserved yet became so loyal and relaxed around Lewis, highlighted what a force for good Lewis is.
For me, Hathaway has been one of the most fascinating characters on TV for quite a while, and I'm quite glad that they didn't just settle him into a relationship - although they've been a bit inconsistent with this, as they've shown him being both quite relaxed in a romantic situation and, at other times, very nervous and unsure how to proceed.