WR's do so much more than that. For example, Larry often chips at the line. You can rely on him to run the exact route he should. If a WR runs the wrong route, or the right route in the wrong place, he's not drawing the defense to where they should be to open up elsewhere. Run blocking obviously. At least twice his smarts got us last second FG's. There's a bunch of stuff we will miss.
Not least of which is the last team you want a body catching player like Isabella up against is the Pats DB's. Those DB's will pluck the ball out of the air while Andy is rocking a baby waiting for it.
Say Larry Fitzgerald retired last year and his replacement was a guy named Bob Smith and gave you the exact same production Larry is giving you anyone here claiming he’s so valuable