Dez is your guy, I get it. He has a very limited route tree. When his prime was gone, so was his usefulness to the Cowboys. All those years in the league and he failed to expand his route tree. That's on him.
I won't even begin to talk about Amari's route running. It speaks for itself. And for the record, there was no creativity last year (same Linehan calling plays for both players). Amari still balled out. This year, sure they're more creative with Kellen's playcalling. But even if Dez played today, the Cowboys couldn't use him the way they use Coop because he isn't a good route runner.
Even if Jason Garrett called plays while Dez was here, Romo had the authority to audible out of a bad play to a more advantageous one.
Dez's best years were with Romo. Even in limited time together with Dak (midseason pickup and 1 training camp). Yet, Coop put up similar numbers that reflect Dez's best years, statically as I posted.