He measured out at 6'1, the same as Collie. He will also run a 40 time very similar to Collie, and yet he will be the first WR taken in the draft. Size and speed are only two components of being a great WR--along with strength, route running, hands, etc.
So if based solely on measurables, Collie is only a "possession" WR in the NFL, then a lot of NFL teams must be stupid for ranking a "possession" WR like Crabtree as the #1 WR in the draft.