In fairness to you, no one really knows if Dez can rebound or not. It is conceivably possible that he could return to his pre "getting paid" form. I don't think he will. You do. I respect your opinion on it and quite frankly if Dez stays I hope you turn out to be right on this issue.
On the other hand, the problem I have with your point of view is that you are conveniently ignoring the fact that he has quite literally underperformed for three straight years (after getting paid) and ASSUME that it is going to take something great to replace Dez' production. You are ASSUMING Dez' production is pre contract signing Dez.
While I agree that COULD happen, I don't see that as a safe assumption. It is quite honestly wishful thinking.
If you are going to assume something (which is fine) why not project Dez going forward based on his most recenct three years? Isn't that more realistic? I mean, Dez is getting OLDER not younger, the wear and tear is adding up on his body, Dak isn't going away, at least this year (moderately safe assumption) and Dez' comments seem to indicate he feels the heat and is panicking at least a small amount.
Dez hasn't said anything about hey I realize I have sucked three straight years so I am going to really concentrate on route running. The indications are that Dez is going to "shut up his detractors" by doing the same thing he has always done. That's probably not a recipe for success for Dez.
When Dez does the same thing he has always done and he gets the same result I don't see Dez looking in the mirror and saying "It's my fault". He is going to melt down and pile on Dak. At least that's the direction it seems to be going. The coaches will be thrown under the bus too. You can see it coming.
So projecting what Dez will do this year he could "go off" and "beast" as the Dez Fan Bois like to say. But isn't it more likely that Dez will decline a little bit more this year and drop off in his production just at least to a small degree?
I think a drop off is more likely, unless he reinvents himself. I would love to see that, but he doesn't seem to see that his failure to progress is part of the problem. If he hasn't accepted that fact then why would he change anything?