I agree with most of the above. He drops too many balls, he doesn't run routes well, and he's a bit small (5'11" 190lbs) to be an elite receiver.
On the other hand, every time he catches a pass he has the potential to turn it into a touchdown.
Since becoming a receiver in 2007, his stats have improved every year.
Yr------Games-rec--yds--avg---yds/game
2009---13-----57---757--13.3--58.23
2008---15-----52---665--12.8--44.33
2007---16-----20---299--15.0--18.75
There's no reason to believe he can't continue to improve, and maybe Martz can make him better than Turner could.
I definitely think, he can be a better receiver than he can be a cornerback, and using him just on returns seems to be a waste of talent.
Do I think Hester can be another Jerry Rice? No, absolutely not. But let's give him at least another year to see how good a Devin Hester he can be. Based on last yrs average, if he played 16 games, he would've had 931 yards. Maybe this year he can break 1000!