#2 Cesaro
Indeed, this topic has been discussed ad nauseum for years. The fact that Cesaro still hasn't been given a shot outside of the tag team ranks is why the conversation continues to be relevant. It's more relevant than ever now that it is fully possible that Sheamus may never return, and if he does, it's more than likely not going to be as a full-time performer.
Cesaro has it all. He has the look. In the ring, he has a very unique combination of size, speed, agility, power, and, well, you can literally name every in-ring style that exists. Cesaro can do everything. The one thing he doesn't have is complete fluency in spoken English, but there are myriad ways to get around that. The list is long enough that we could spend days discussing it. In the absence of speaking ability (which he is actually qute good at thanks to having very strong timing), Cesaro posessed one extremely important aspect of a true Superstar. Presence. When a man like him walks into a room, or an arena, you can't help but stop what you're doing and look.
WWE clearly trusts him as a safe wrestler who can help others look good. He had a series of great matches with Ricochet shortly after the debut of "The One and Only", and more recently was tasked with putting together a match with young Saudi Arabian star Mansoor, and he absolutely knocked it out of the park.
He can be a good guy, he can be a bad guy -- he can be anything you want him to be. He can be World Champion, he can be United States Champion (too bad he's on SmackDown, as a program with AJ Styles could be stellar), or he could be a man for hire. Have a problem? Cesaro can solve it. He could be a one-man modern version of the APA.