I think Manziel has a high ceiling and I saw nothing Saturday night to dampen that assessment. He looks plenty mobile and I think his arm strength is probably underrated by most. Another poster mentioned his quick release... there was one particular play where Manziel, with the pass rushers closing quickly, cranked his torso and in a flash whipped a dump-off to the RB to his right to avoid the sack. It was eerily reminiscent of the kinda play Romo routinely makes.
It's not a question of IF for Manziel, only WHEN.