I would probably say CM Punk
CM Punk is one of the biggest assets in Smackdown today and he is the one responsible to carry Smackdown. Jeff Hardy winning at Night of Champions was for the sake of storyline because if Punk won, than Jeff would have absolutely nothing to do until Summerslam. Other than that, WWE has done a fantastic job with CM Punk and how he's progressing. CM Punk's momentum isn't killed yet and he took another huge heel turn when he attacked Jeff after the matches. CM Punk's heel turn was picture perfect and he was doing a great job playing his heel gimmick. CM Punk is actually considered a major superstar now and he has been getting massive popularity from the fans. He's also had some great matches with numerous superstars such as Jeff Hardy, John Morrison, Chris Jericho, Edge, and others. CM Punk has also been the IC champion this year and won the MITB the second time. CM Punk has been impressive this year and I'm glad that WWE is finally booking him correctly.
CM Punk's gimmick has also been perfectly played out so far with him preaching about how great it is to be straightedge. He is already getting a huge amount of fan heat for his gimmick. CM Punk has been the conflicted champion and its exciting to watch him every week because he is unpredictable. CM Punk has done a great job in his promos expressing his distaste for the fans and Jeff Hardy. WWE might be possibly turning CM Punk into a coward, but so far i don't think any superstar has been booked as well as CM Punk. His assault on Jeff only furthered his heel gimmick and he seems to be the one to take the world championships away from Jeff by Summerslam. CM Punk has also given us some fantastic promos about being straightedge and he's definitely elevated his game compared from the past. Chris Jericho is also right up there, but we can't deny that CM Punk has improved his status in the WWE by a wide margin.
BQ: Eugene is actually a good wrestler and his purpose in WWE was to take care of some of the younger talent and newer superstars. Eugene's character wouldn't interest the fans that much because there are weird superstars like Goldust and Eugene joining WWE with his gimmick wouldn't be a wise decision. I personally don't think he should have been released because he's a talented wrestler and they should have given him a different gimmick that would actually work. I don't understand why WWE released Eugene.