In issue #10, Kate starts using the Patch to try to quit smoking.
A little thing? Not to those of who you who know the difficulties of kicking the habit. Kate decides to quit smoking because her son asked her to, I believe.
It's just one example of character development. A lot people complain that in most A-list superhero comics, there's no room for character development. Everyone pretty much has to stay the way he is, at best oscillating between two points on a personal personality pendulum ("I am lone dark vigilante!"/"I'm the paterfamilias of a whole of colorfully clad crimefighters!").
Manhunter isn't doing that. She's contradicted her career as an officer of the court by becoming a vigilante. She contradicts both of those by later becoming a defense attorney. She works to expand her cast of supporters for the vigilanteism. She tries to quit smoking.
Where is she headed? Will she succeed in anything she's attempting? I don't know. I know that Superman will always win; I don't know whether Manhunter will.
Most important to me, all this goes on without pages and pages of overstuffed word/thought balloons of self-pity and self-doubt.