Yeah, Tone needs a role aside from the best or top tier at literally all things in all contexts.
Is Tone really getting destroyed by Northstar at long range? North has no health and, at long range, mostly just her primary. If Tone lasts just two shots, that Northstar is getting shredded or fleeing for her life.
And in close, who is she getting destroyed by? Not North or Legion. Scorch would be dangerous sure, but how do you let a Scorch corner you as a Tone? Ion can block all of Tone's attacks sure, but they have limited energy and you can just feint a few attacks to force them to waste their shield. Also, during that shield you're taking no damage and can freely reload while your dash and shield steadily refresh.
Ronin is the only option left and it's a little weird that being at a disadvantage to a Titan purely designed around close range combat is Tone's biggest weakness. Even in that context you still need to just land two shots for missle lock. If the Ronin doesn't sword block those, he's damn near toast. Even a flailing Tone ambushed by a Ronin is going to take most of his health unless they nail perfect blocks.
Tone's "weaknesses" are less weaknesses and more times she isn't just going to wipe the floor with the opposition.