I'd say the main difference between Higbee and Kelsey is opportunity. The former put up crazy numbers when given the opportunity last year. Won me money in fantasy football.

Imagine what he could have done if Goff extended plays like Machines.
Woods was a good WR who battled injuries and horrible QB play in Buffalo. But Brandon Cooks put up big numbers with 3 different teams. He didn't keep getting dealt for 1st round picks & get that big contract because he was chopped liver.
While I'd rather have Hill over Cooks, I'd also rather have Woods over Conley. And, IMO, both Cooks and Higbee could have been Pro Bowlers (popularity contest) with the same amount of opportunities in KC, too.