A total waste of air time.
Even in Mexico he is extremely limited in his ring skills. He only has 5-6 moves that he does all the time. Mysterio needs a set up to his spots that you can see coming a mile away, but at least when he was in the ring with Eddie G, Dean Malenko, Jericho, or Juvie he could freestyle the match and pull stuff out of the air because his opponents knew what to expect and flow into it.
Unlike Mexico where Mistico could expect Ultimate Guererro, Hector or Perro Aguayo, Jr to carry him through a decent match, there is no one in the WWE that is going to be willing to do that. A 25 minute match in Mexico would see Mistico spend 3 minutes hitting his spots and 22 solid minutes of getting the stuffing beat out of him. Dude made a living off selling on the mat.
Oh and standing around pointing his fingers all over the place is consider one of his moves.