Don't remove Duskblade or anything, rework it.
I realize that champs that build Duskblade like Talon, Quinn, Wukong, etc. are strong right now and Duskblade is very unfun to play against. It just gives straight up burst, how interesting. But I think if it was straight up removed, AD assassins would be gutted, as their core item would no longer exist.
I think Riot should do something to give Duskblade a passive that helps AD assassins in some way, and is interactive at the same time. I'm not sure what Riot can do to achieve this, but they surely can make something much better than what they have now.
(If it means anything, this is from a Talon main.)