I spoke to someone last week who assured me that Shumpert blew the Knicks away during his workouts. From this video it's clear that he's working on his strength and lift and his catch and shoot ability. The shame is that he's not getting the chance to work on the timing of these essential skills because that's the biggest adjustment to the NBA off the bat in my opinion. You have to be able to recognize and read when you can get your shot then be able to knock it down.
That takes time.
All in all, very impressive.