I agree on a lot of the changes you mentioned and I think they would make nightcap a better stealth character.
Not too sure about the eyeball thing though. Sounds like it would be too good for a passive but maybe an expensive upgrade.
I think nightcap should be a better assassin as well. In other words she should get into enemy lines, Kill someone, and get out. I think she should achieve this by dealing extra damage while she is attacking someone behind. I think this would catch zombies off guard and by the time they turned around they might have died already.
