Ben has actual violence/anger issues, he is not remotely emotional stable and is more murderous and egotistical than Tse. He is obsessed with violence and warfare, which he is certainly good at, but nothing else.
Cammy is spoiled rich bitch taken to the absolute extreme. The type of person that is actually incapable of productive function and can only survive thanks to an excess of wealth. Historically her type is always an utterly disastrous ruler.
Not much is known about Zhang, but he's relatively reasonable.
Tse is cruel and doesn't respect life, has an excessively high standard which scorns those who don't meet it, but is at least relatively functional. Without development he'd probably be tyrannical but at least functional, and because he's functional there's possibility for improvement in his character.
Tubeppa has expressed Ben-style sentiments of destruction but no actual ideal
Tyson is another Cammy
Luzurus seems okay if somewhat incompetent
Sale-Sale is another Cammy
Halkenberg has Tse-esque ideals but has repeatedly hesitated in engaging in actually taking necessary action, although his beast also implies a Ben-esque warlike nature
Everyone else are basically just children
So out of actual immediately-functional King candidates there's basically just Tse, Tubeppa, Halkenberg, Luzurus, Zhang. We know pretty much nothing about Zhang and Luzurus, and the only princes to have expressed any kind of actual ideal whatsoever are Tse and Halk, who are apparently also friends, and perhaps Luzurus. I'd personally bet Halk or Luzurus but they'd also be the least interesting kings due to being the most typical, one of the kids becoming king would also be too typical. I hope for Tse because him becoming king-worthy would be more interesting than some coming of age shit with one of the young princes or one of the already-decent candidates simply surviving to the end.