Agreed. I would add, though, that's a very high bar. Chances are that no matter who they draft, even if it's a 1st round pick, won't be another Kupp or his equivalent.
But I'm noting that you feel they'll need someone better than Whit when Kupp moves on. I can't say you're wrong...or right for that matter. Time will tell.
Don't count Whittington out. I have more than just a feeling he could dominate the third receiver role. Yes, he has to get healthy first, and I love what Robinson and Johnson have done for us...but Whittington offers the same Kupp/Nacua role that makes this offense so hard to defend. Defenses don't know where the ball is going because all three are such impressive and physical blockers and all of them can motion out and line up anywhere. Like kurtfaulk said, the offense couldn't do anything once Whittington went down in the Packers game, and he was a force when he played them and the Bears.
Would I sell what little remains of my already-sold soul for a Luther Burden III in next year's draft to upgrade Whittington? You're damn right I would, but until then, I think a trio of Kupp, Nacua, and Whittington is going to be our best bet to win the division, playoffs, and Super Bowl.