Talent alone.
OK.
Well, since QB is by far the most difficult position to play well in sports, Allen is going to, and should be, ranked higher than any WR in the game.
Think of it like a new league staring and all the players are released into a talent pool. You are one of 32 GM's and you hold the 5th or 6th pick. Josh Allen is on the board as well as Diggs, Adams and Hopkins. If you select one of those WR's before Allen, your stay as a GM in the new league most likely will be short lived.