Watkins is the X because he's skilled enough to get off press coverage. So, you want to move him, fine. Then you put someone else there and they cannot get of the ball. Because if they could they'd be an X receiver... So to "move" a player you basically give up your X route.
I happen to think cVay knows who should be the X (on the LOS on the 2 receiver side) and who should be the Z and who should be the slot and who should be in mortion.
If we were 2-5 and not 5-2 then, yeah, maybe there would be a case to move him around. And it may be possible to put ye and Reynolds (the backup X) in the game a the same time when Reynolds is a competent X... so I wouldn't rule it out, but we have a #1 receiver player the #1 position and we are winning and scoring points
I'd give McVay's expertise a few more games.