It seems we have this discussion every year before the draft. IMO the evidence is clear Thompson doesn’t pick the “best player available” and in fact no GM does in a pure fashion or it would occasionally lead to absurd results, like consecutive picks at the same position, and/or multiple players who don’t fit the team’s system or needs. I believe Thompson uses “best value available” and he does that by taking into account the players currently on the roster. Also as I’ve posted before (no doubt ad nausea to some) I believe most teams divide their board into talent tiers and when a player from a higher tier is available, even if he’s not at a position of need, even if he’s at a position of strength, I think Thompson’s philosophy is to either take that player or trade down for value (not just for the sake of trading down). IMO that explains the pick of Sherrod, for example: I’ll bet he was elevated on the Packers board because of the Packers’ need at OT. And it explains the Rodgers’ pick: To have a player from the top tier at the most important position in football for his first pick as GM, at pick #24, had to be a wet dream for Thompson.
So if a WR is available at #21 who is the highest rated player (by a significant amount) on the Packers’ board I’ll bet Thompson grabs him. Even though WR is not relatively a significant need.