I love Domino But she's the only one of the four I have as a 5* so I'm not going to vote lol. Shes been amazing in variant and act 6 and destroys uncollected EQ. I suspect Namor will win but we'll see.
Namor, because of his dupp ability to basically ignore DoT effects on him while he's hitting (so good for Suicides and Maybe Biohazard ?). Also he can have some insane hits and doesn't rely on effects such as bufs and debuffs.
Also the other rankup options you provided have minor imperfections. Covus needs the first fight to ramp up, which is the perfect place to lose health. Domino's dmg output is inconsistent and too much chance-based, which makes her hits impossible to predict (that's annoying especially towards the end of a fight). About Nick Fury, his dmg relies on bleeds (many champs are immune to these) and his "true form" makes him very good, but he is always on 30% hp or lower, which makes any mistake lethal for him.
Finally I have to say that it's just my personal opinion and you should rankup the champion, whom you can play the best and ideally whom you like.
Comments
Also the other rankup options you provided have minor imperfections. Covus needs the first fight to ramp up, which is the perfect place to lose health. Domino's dmg output is inconsistent and too much chance-based, which makes her hits impossible to predict (that's annoying especially towards the end of a fight). About Nick Fury, his dmg relies on bleeds (many champs are immune to these) and his "true form" makes him very good, but he is always on 30% hp or lower, which makes any mistake lethal for him.
Finally I have to say that it's just my personal opinion and you should rankup the champion, whom you can play the best and ideally whom you like.