With the fresh and new artifacts out, RoR mge is possible and I've compiled a tier list for how good each survivor do in a 1v1. 

E:
Coming in at the bottom of the list, the Engineer. His sentries can't lock on and mines could be easily avoided. His m1 has no range and the harpoons take so long to fire you'd be dead before you got any damage in. 

D:
Next up is Rex and Mul-T. Rex's tangling growth doesn't work on players and abilities that damage yourself will just result in you dying faster. 
Mul-T's only decent primary is his rebar since it's the only thing in his kit with range. But it honestly tickles and Mul-T just ain't handy. 

C: 
Commando and Mercenary can both shred other classes with ease. Commando's phase round does insane damage and can score a kill in one or two hits in close range.
Mercenary's attacks do alright damage but he is hard to track down and hit when he is dashing and in his iframes. But if you just stay away and snipe them or have mobility, these two gets countered pretty hard.

B:
Huntress and Artificer have both mobility and long-range capabilities. Huntress's ballista is oppressive (if the Huntress can aim), and Artificer can just hover and chuck fireballs although it does take some time to kill. 

A:
Obviously, Loader is the strongest. No matter what class, you're just a sitting duck waiting to get punched into the next map. The only thing that could face off with a Loader is another Loader or an Artificer with god aim.