This argument that an RB should not be taken in the first RD is so silly. Some that were taken in the first RD:
Emmitt smith #17
Barry Sander #3
Marshall Faulk #2
Ladanian Tomlinson #5
Adrian Peterson #7
Walter Payton #4
Jerome Bettis #10
Eric Dickerson #2
Earl Campbell #1
Edgerrin James #4
Marcus Allen #10
These guys were pretty good. I had to stop. There are more. Most of the greats have been taken in the 1st RD. The only reason Leveon Bell was not taken in the first round is because GMs told themselves that RBs should not go in the 1st. Everyone knew how good Leveon was. He surprised no one.
Recently we have Gurley, Gordon, and Zeke. This year, Fournette, Macaffrey, and Cook.
Hey, maybe QBs shouldn't go in the 1st. Look at Brady, Flacco, Romo, etc
Maybe TEs shouldn't even be drafted. Look at Antonio Gates.
Cook is a 1st rounder. Period.