First - Is he still being treated like a WR1 and attracting the attention of the top corner by teams who work this way? And if so, is his presence benefiting the other receivers and the O as a whole in ways beyond his statistical production?
Second - Why is his production as low as it is? I think most of us thought, with the way the Goff is playing, that Watkins would be a monster in this offense. The only way to determine the answer to this question is to spend a lot of time with the all-22. Is he in fact, open often and not being seen? If so, is this because Goff has developed better chemistry with Woods and Kupp, or is it because the offense calls for Goff to mostly focus on one side of the field and that side tends to be the side away from Watkins, who seems to often be the only received on the side where he lines up? If the problem is that he is open and being ignored, can that be fixed? Is the plan for next year that Goff, having grown and developed his skills. is now scanning the whole field?
Third - Given the other receivers we have and their production, how badly do we need him? If we pay Watkins, who don't we pay, given that money is finite? Would it be bad for the team morale to pay Watkins more than Woods when Woods' production has been better.
In the end, if he thinks he needs to be paid like a top 10 WR, we probably lose him in FA. We just have too many other proven players that need to be paid.
But as others have pointed out, if we get a compensatory pick for him leaving in FA, hopefully a 3rd, the one year rental cost us not a 2nd rd pick entirely but a drop from bottom of 2nd to bottom of third.
I would love to be in the meetings when McVay and his staff evaluate Watkins and answer to their satisfaction "why has his production been less than expected?"