I don't want to wax too philosophical here, but returners are the single most overrated position on the field, followed closely by wide receivers. As fans, we
think they have a big impact on the game precisely because their flashy plays are so rare that they stick in our memories, whereas we tend to overlook the players who do contribute on every single play. (I could go into a long explanation of the neurophysiological mechanisms that make us unable to avoid this mistake, but for now I'll just say to look up
"long-term potentiation " if you are curious.)
Returners may affect the outcomes of a few games here and there, but over the course of a season, their impact on a team's win/loss record is statistically indistinguishable from zero. A buddy of mine who is doing postdoc work in biometrics applied the statistical tools of his trade (
principal component analysis in particular) to a gigantic body of data and showed this pretty convincingly. Returners hardly make a blip against the background noise.
Think about Randall Cobb, for example. As fun as he was to watch, how many games were actually decided by his return skills? None. His most dramatic return performance came in a game the Packers lost. He made much more of an impact as a receiver -- but it was an impact many other receivers could have made, especially with Rodgers throwing the ball to him. Receivers are largely interchangeable parts these days.
It would be a massive waste of money to chase down another returner in the hopes of getting a few extra yards of field position. Plenty of studies have shown that starting field position doesn't have anywhere near the effect on a team's scoring potential as the pundits and talking heads make it seem.
The Packers should be focusing on revamping the positions that would make a substantive impact in every game: putting some beef on the offensive line to protect Rodgers and finding a reliable running back would be a great start. Adding another defensive back or two would be helpful as well.