Cook is a 1st round lock at QB.
Probably not. Completion percentage across the spectrum doesn't correlate between college and NFL success, but completion percentages under 60% do, and therefore has become a key indicator.
Connor Cook is a 57% passer this year, never a season over 58%.
The list of sub 60% passers drafted in the first round since 2010:
2011 Jake Locker
Not exactly a long list. It should also be noted that while 60% is the traditional number, for reasons listed above, the number is closer to 65% in recent years.