Herbert had a really poor collection of wide receivers & TE's to throw too. He had Darren Carrington as a freshman and a couple of seasons of Dillon Mitchell. The rest of his WR quality was the level of Brendan Schooler and Johnny Johnson. Or, he was throwing to tiny receivers like Charles Nelson and Jaylon Redd. And the only decent TE he had was Jacob Breeland, who missed half of Herbert's senior season.
compounding that was that in Herbert's junior and season seasons, the Ducks actually led the nation in dropped passes
also, other than 2 years of Royce Freeman, one of which he was hampered with an injury, Herbert had no elite RB's to absorb attention of the defenses
contrast what Herbert had as support to what Mariotta had as support...
RB's: Kenyon Barner, DeAnthony Thomas, Byron Marshall, Thomas Tyner, Royce Freeman
WR's: Bralon Addison, Josh Huff, DeAnthony Thomas, Byron Marshall (switched from RB), Keanon Lowe, Devon Allen, Dwayne Stanford, Darren Carrington
TE's: Colt Lyerla, Pharoh Brown
Just a wealth of targets and supporting talent compared to Herbert. For all the talk about Cristobal's recruiting chops, there has been a real void in recruiting skill positions in the last couple of years of Helfrich, Taggart's one season, and Mario's first couple of years. At QB, RB, & WR. It has been mostly 3-star talent, or less. That will have an impact on offensive consistency