Brian Braddock has a couple of strikes against him. He was essentially created to be the English Captain America, and he's a little like Marvel's Shazam. His powers are magical in nature and were originally given to him by a wizard. Cap Britain has had a tough go at it. His character has been through costume changes, revamps, and ended up having his powers tied to his emotional state. If Braddock is feeling a bit emo, he won't have as much gas in the battle tank. He's also a "brilliant scientist with a Ph.D.", just like a hundred other superheroes. What Captain Britain lacks is a certain "it factor" that makes him stand out and connect with readers. His solo book was canceled. A few incarnations of his team, Excalibur, have come and gone. He was kind of a member of an Avengers sub-group for awhile, but that went away too. In a modern culture saturated with superheroes, there just isn't a lot of space at the table for Captain Britain. Another British upstart like Brian Falsworth (Union Jack) could step into the role and give the character a shot in the arm, with a new attitude and maybe a new, subtle outfit.