Since the scouting era began, the draft has been a fairly accurate bellwether for success in the NFL. Late round gems like Tom Brady (who went in the sixth round) and first round bombs like JaMarcus Russell and Ryan Leaf are the exception, rather than the rule. The draft is the first introduction for fans to the league’s future leaders. It’s also the first time we see a lot of these guys without helmets (the photogenic Robert Griffin III notwithstanding).
Furthermore, teams that don’t do well in drafts tend to run into trouble in subsequent years. Peyton Manning-era success for the Colts came with the price of year after year of low draft picks, part of the reason their implosion without him last season was so spectacular.