It's a pretty satisfying ending since it addressed almost everything. The opposing mob, the assassin, his identity being revealed; and the underlying question of what he'll do with his looks when hiding becomes unnecessary was dealt with the shady doctor being a dick and leaving him as is. (+tits) The shady doctor was more like a plot tool than a character, so focusing on him too much would've probably hurt the story, I think.
A reaction to his identity from the kids would've been nice. A line like "She's a mobster!? It explains her strength... but we seriously can't see him as anything but Hiromi-chan." or something would've been good... although it might be implied, it's not acknowledged explicitly and makes it feel like the reveal didn't matter. The son's dislike for his dad was somewhat resolved, or slightly implied since he saved their life, but the previous concern is still there.
It's not too bad.
Maybe I'm too accustomed to mangas dragging on forever and relying on their gimmick.