Talon Changes.
Aside from lacking mandatory Project Skin. For the upcoming assassin update, you could change his passive to have his E 'reset' on kills of marked targets which gives him a second cast, without the debuff attached, and make his "Sever Tendon" (E) a slightly higher range (like 1 or 2 Teemo's) skill shot blink, with a small aoe debuff (1 3rd, to half the range of Rake) instead of the single target one.
Passive >
Killing Marked Target grants second E cast without Debuff, Second cast does not alter or modify Primary E cast Cooldown.
E Cut Throat >
Slight range increase, Skill shot, Small AOE debuff, Still a blink.
Rest remains intact.
No, this doesn't make him like Katarina, and regardless, they have the same Superior.