Swagger isn't strong enough to stand on his own. He's a "heck of an athlete", to use good ole JR's phrasing, but he has the personality of a wet sponge. He just can't act whatsoever. Every time he opens his mouth, he makes it abundantly clear that he doesn't believe in what he's saying. His facial expressions and body language are a dead give-away. Coulter makes you believe, makes you forget that he's an actor playing a character. The only thing that Swagger makes me believe is that he needs to go back to acting class.
But then again, it's just the sort of thing that you either have or you don't and Swagger has never had it, nor has he ever shown an inkling of potential to build it. It's a shame because the guy can actually wrestle both in and out of the ring, but you can tell that he just isn't comfortable portraying anything but himself.
Perhaps if Coulter took on a second guy to team up with Swagger, it would take some of the attention of Swagger. Having the spotlight on him, even with Coulter as a mouth piece, really highlights Swagger's weaknesses. Team him up with another mid card guy who can't get over on his own.