As the Lions continue to show an unreal amount of interest in Sammy Watkins, the debate here seems to revolve around whether trading up for him is worth the extra picks in what is considered a deep draft at a deep position were any WR would be at best considered the third fiddle behind Calvin and Golden Tate. The point against taking him seems to be centered around the WR3 position and its minimal impact, while also considering trading up for a player whom will not be a starter in the near future. In determining if this is a reasonable perspective, we first must define what a starter is in today's NFL that specializes in sub packages.
The fact is that currently defenses are playing nickel around 65% of the time on average. Then it is reasonable to determine that 65% of the time or more an offense has at least 3 WR on the field or at least 2 WR plus a Gronk or Graham type TE. We know that the Lions used the nickel as their primary defense last year, with Ashley Palmer playing only 34.1% of defensive snaps while Levy and Tulloch played 98.6% and 99.6% of snaps last year. By comparison Darius Slay played about the same number (32.9%) as Palmer, and he was the fourth CB in snap count and was injured for part of the year. From a defensive perspective, the Lions as most teams are playing with 6 man fronts with 5 DB's in the game most of the time. I think it is reasonable that even though Palmer is listed as a 'starter', Bill Bentley as the nickel corner who played 127 more snaps than Palmer in 3 less games is really the 'starter' on defense.
Now that we have determined that defenses are defending 3 WR sets the majority of the time, I think it is pretty safe to say that WR3 is in fact a starter on most NFL teams. Due to injuries to the Lions WR's last year it isn't exactly clear how often they played with 3 WR, but I would argue that it was more than the league average since they are consistently among the league leaders in pass attempts. Now we can see that in fact a WR3 is a 'starter' in today's NFL, and would in fact be the only position on the roster where there is no clear starter on this team. This would make WR3 the top priority still left to fill this off season.
It seems as though the Lions also share the same view presented here. Whether trading up for Watkins is worth it is till up for debate. If they determine that Watkins is the best WR prospect since AJ Green and Julio Jones like must experts seem to place him, then I would say go and get him. If on the other hand Watkins is more comparable to the 1st round WR's from last year, then I would say they should pass on trading up.