Something people may not be taking into account is that jacobs ran his 40 on what appears to be grass/turf, opposed to the track that the combine performers ran on. This isnt by any means a wholly accurate conversion, but generally, the conversion from grass to track is 2%. So you would subract 2% (.092) of his 4.6 time from the 4.6 itself, giving you roughly 4.5 time (not taking into account the inaccuracies of hand times, which could be faster slower dependent on a multitude of variables, injuries, and possibly disinterest).
I feel a smarter athlete will do well enough to get drafted but not perform so well that he ends up getting drafted by a bad team with a top pick. An ideal situation is penny where he can sit behind a starter and learn the nuances of his position at his pace and takeover when ready, opposed to a ronald jones who was expected to take the reigns immediately and was exposed, which potentially can destroy a persons confidence, inhibiting any progression he may have had if he were in a better learning situation/environment.
Just my take.