A good throwing QB can elevate his receivers, just as a poorly throwing one can degrade them.
2016 - Equanimeous St. Brown came close to getting a 1000 yard season, and really stepped up his game, becoming the WR1. He had Deshone Kizer throwing to him.
2017 - St. Brown barely broke 500 yards, and came close to having his neck broken several times reaching for errant passes by Brandon Wimbush. The offensive line was actually significantly better this year, too.
2018 - Miles Boykin breaks out when Ian Book takes over as QB. Up until that time, he had only 9 receptions for about 170 yards. After we finally got a decent passer, he had a very fine season that should have been a 1000 yard season. Chase Claypool and Chris Finke also had nice seasons as well.
I wish that St. Brown had stuck around for 2018, that he would have had a very nice season with Book at the helm.
Regardless of who starts, we'll have a QB who can make all of the throws, to all parts of the field. Teams won't be able to squat in short / medium zones, and this should open up more holes for the running game.