That's the whole point about making him the traitor, right now he doesn't seem interesting but if he gets revealed as the traitor then he will become interesting. The only reason why some people like you think it's lame is because Kanjuro hasn't gotten that much focus so his character overall is not as interesting as compared to the others, however if he gets revealed as the traitor then his character will actually get some focus and he will become interesting but it really depends on how Oda does it.