As a manga lover I on the contrary think Watsuki does deserve a second chance, it might be funny that a guy who wrote a manga with the theme of redemption doesn't get the chance to redeem himself. Yes it does leave a sour taste in my mouth and of course I can understand people thinking "what if by the money he's getting from me purchasing Kenshin he gets those videos, which means I'm supporting unwillingly child prostitution?". If I can sympathyze with a character moving from bad to good, a human most certainly deserves a second chance.
On another note, much like I can listen to Michael Jackson's "Heal the world" and I think it's an amazing song, and not hear "Think about the children" and get pissed like hell, I can disconnect my feelings towards Watsuki as a preson and appreciate Kenshin as a great work of art.
What do you think he needs to do in order to atone and have a fair chance to return as a mangaka?