Sure, we can get a fresh face in the WWE Championship scene. But I wouldn't like to see any of those people listed competing for the WWE Championship, let alone winning it.
Carlito did defeat John Cena in his first WWE match to win the United States Championship. That did not help his credibility much, same with many others who won titles on their debut. Carlito is barely a staple on Raw. Your lucky to see him once a month. He is such a talented wrestler, but as long as he's on Raw, he'll go nowhere.
Jack Swagger would have been the best choice, but unfortunately, he's been less than impressive in his 3-month stint on Raw. On ECW, Jack Swagger was the shit! He was constantly in the title scene for 6 of the 10 months he was on ECW. On Raw, he's barely getting recognized. I'm glad to see that he's being added to the United States Championship, but first we will have to see how it plays out. If he gains momentum, we will see if he can go to the top.
Kofi Kingston is my favorite of the list. He is, in my opinion the greatest United States Champion since it's resurrection in 2003. He is such an amazing performer, but for some reason... some people couldn't care less about him. I love the guy! But even as such a strong champion with such a strong reign as champ, he's still very underrated. When he does lose the U.S. Title, I'm afraid that WWE will let him get lost in the shuffle again. He has the talent, but he's not yet ready to go after the WWE Championship, no matter how good he is.
Mark Henry is a main-eventer on Raw that does not need to go after the WWE Championship. As long as you see him on Raw, he'll be just fine. He hasn't been the best of champions in the past, which is probably why he hasn't held many titles. But if he's being showcased regularly, then he doesn't need a title.
M.V.P. is the most likely of the list. I say that for the simple fact that M.V.P. is the stronger link of the team with Mark Henry. Henry may be the "World's Strongest Man", but I think M.V.P. is the stronger link between the two. If you think back, at Breaking Point, I believe Henry was the one who got pinned in their tag team title match, and last night on Raw, Orton pinned Henry to win the match for his team. I think this tag team is helping M.V.P. get elevated to the main event. He even changed his ring attire to show off the guns. Haha.
The Miz is just boring to me now. I used to really like the man. I thought he had a lot of charisma, and I used to think he had potential. Now, I think his ring and still good mic skills are declining. I hate his finisher. I no longer think he should be made into a serious threat to the U.S. Championship. His ring skills are the only thing going for him.
So, I'm not saying that they can't be added to the WWE Championship scene. It's just that I don't see it happening. If I had to choose, I'd say M.V.P. is the most likely.