When you take a look at the film and each of their skillsets, however, you quickly see this is likely not the case.
While Cobb would be able to play in the slot as a receiver for the Cowboys if he signs, his value extends much further than just a slot receiver. Where Beasley makes his mark with precise route running, short area quickness, and 3rd down reliability, Cobb is much more of a threat after the catch. He's not the route runner that Beasley is, and really isn't an upgrade over Beasley as a receiver, but Cobb would be able to help the Cowboys' become more diverse in their offensive schemes.
Similar to Tavon Austin, Randall Cobb can be used in pre snap motion and jet-sweep packages, as well as a traditional running back. A college quarterback, Cobb's versatility is what makes him so attractive to NFL teams. Cobb would actually fit more of the Lance Dunbar “scat back” role of sorts for the Cowboys than that of the Cole Beasley slot receiver role. His versatility, however, allows him to carve out a lane within the offense which they haven't quite had before.
Another area Cobb could help the Cowboys is when the play breaks down. With experience in the Packers offense playing with arguably the greatest improviser we've ever seen in Aaron Rodgers, Cobb would be able to help Dak Prescott down the field when he breaks the pocket and the play is off schedule.
So often last season we talked about how the Cowboys offense is reliant on remaining on schedule, staying in front of the chains and not having to force the ball downfield. Unleashing the Mississippi State version of Dak Prescott, where he can improvise and use his legs to create big plays, tends to be when this offense is at its best, however.
Randall Cobb won't be a Pro Bowler if the Cowboys sign him, and depending on the money he receives, it might not even be a lock that he makes the final roster. But Cobb would be an exciting addition to a Cowboys offense which has lacked “creativity” over the last few seasons, and is looking to reinvent themselves to a certain extent.