Lots of Shelton Benjamin love here and I generally don't see why. It amazes me that people consistently gloss over the fact that Shelton was given multiple and lengthy runs with both the United States & Intercontinental Championships, wins over guys like Chris Jericho, Triple H & Rob Van Dam and spots in high profile matches like MITB but was never able to get himself over to that next level. No one has ever denied Benjamin's athleticism, but the man is as bland as it gets in terms of personality, charisma & mic skills. He's the exact same way in ROH right now as he's was in WWE. There's a big difference in someone that's misused and someone that just couldn't get over no matter how many opportunities he got. There's only so much Vince can do. He can give you opportunities, the rest is up to you because he can't just wave a magic wand and command fans to rally behind you.
As for Carlito & Kennedy, look at the circumstances. Carlito has a reputation of being extremely lazy backstage and, allegedly, has a sense of entitlement because of who his father is. Carlito failed a drug test earlier in his WWE career and his second one resulted in his termination because he refused to attend rehab. As for Kennedy, you're kidding right? The WWE was pushing this guy hard towards the main event level but he kept getting injured. Kennedy spent pretty close to half of his 4 year run in WWE on the shelf due to injuries. He won MITB but they had to take it off him so he could heal up, thereby losing whatever momentum he had & had to start all over again. It was originally intended that he be Vince McMahon's illegitimate son but he gets injured, so the idea was scrapped and turned into a comedy angle instead. He comes back yet again from some sort of injury and wrestles in a six man tag match as his first match back. Reportedly, he almost injures Randy Orton during the match. The WWE invested a lot of time in Kennedy and whether it be due to injury or any other factor, they got very little back in return.
As far as someone that I think they've dropped the ball with, I'm looking at Jack Swagger right off the top of my head. Swagger does have some charisma, some legit personality, he brings a lot of credibility as a mat wrestler to the game, has a good but unique sort of look and can go inside the ring. It's true that Swagger did become World Heavyweight Champion in WWE but his reign is looked at as one of, if not the single, weakest reigns in the history of the title. Swagger has improved in terms of using facial expressions & body language to help sell an angle and tell a story, he's got the ability inside the ring, but he's been a glorified jobber even during the time he was World Heavyweight Champion. I'm not saying Swagger would've been an all time great or even a long term main eventer, but I think he could be a much more viable asset to the WWE than as a high profile jobber.