I think he's more just not Ling, who is really the only Sui sibling considered to be brokenly strong.

I've heard he is good, but not in comparison to Mountain, because he doesn't really do the same role as Mountain. Which makes sense if you consider that Fighter is such a messy archtype where most of the archtype isn't considered good anyway.

Like it's not good to compare him to mountain just because none of the fighters can do what mountain does, let alone as well. His S2 is just completely unique of the archtype.

Honestly I think Dusk is the weakest. She's very expensive compared to some of the absolute killers in the caster group, many of which also have more effective AoE due to Dusk's slow attack speed.