I mean they did buff his number 1, It has instakill feature now at 25%, If you kill someone with it it full heals all your shadows, And if you dont have max shadows when you kill a target with soul punch or 3 secs after it hits, It turns into a shadow, Which is cool I suppose, It helps you get those scorches shield ospreys and the like.
Is this optimal soul punch, Hard to say when wukong got his number 1 skill from one of the worst in game, Upgraded into one of the best in game, So its hard to know what could soul punch have in a perfect world.
But like I said, At this