watch his elbow he brings it back. tebow does a loop, Nassib has a windup i'm not saying he doesn't but it's pretty quick wind up and good motion, in the video you posted he does drop the ball down by his hip but it comes straight up and he drives it, his motion with a minor tweak would be ideal. tebows was unfixable, nassib just needs a minor tweak
So like I said, closer to Tebow than "perfect". He throws well, good velocity. It's just not mechanically sound.