William Regal, Carlito, Christian, Eddie Guerrero all comes to mind. A couple of them was criminally underused sadly.

John Morrison had a ton of potential, but was never given the big chance imo. His greatest match in WWE to date is still his match against Evan Bourne during a WWECW episode.

When it comes to the girls, I think WWE really dropped the ball on so many talents. But one of the biggest wastes imo was Alicia Fox and Maria.

By the way, Lita comes to mind when it comes to charisma. I don't now about one single wrestling fan who hates Lita, lol.