Swagger's WWE career is a case of wasted potential, much like other midcard stars such as Wade Barrett, Damien Sandow and Cody Rhodes, all of whom have left the company.
WWE pulled the trigger too early on Swagger winning the Money in the Bank briefcase at WrestleMania XXVI in March 2010. He successfully cashed in the briefcase later that month after defeating Chris Jericho on SmackDown:
Swagger didn't have the charisma at that point to be one of WWE's top champions, leading to an underwhelming title reign. Many fans have likely forgotten he held the World Heavyweight Championship in the first place.
The arrival of Zeb Colter as Swagger's manager in February 2013 was a step in the right direction, since Colter could effectively speak on Swagger's behalf and elicit a strong reaction from the WWE Universe.
Shortly thereafter, Swagger challenged Alberto Del Rio for the World Heavyweight Championship at WrestleMania 29. A little over a month before WrestleMania, though, authorities arrested Swagger for allegedly driving under the influence. That effectively ended Swagger's push—his WrestleMania 29 entrance wasn't even shown on the live broadcast.
In the years since, Swagger floated around the midcard without any sustained direction.
His release from WWE makes sense for both parties. There's little reason to expect Swagger's WWE arc would've changed if he had stayed with the company, and now he's free to pursue outside opportunities, whether in Impact Wrestling or on the independent circuit.