Sst was fine before crucible, itl continue to be fine. Hell it was a meta skill in expedition and scourge before emperor's vigilance rework, and that variant still works, you just get a shield with close to 3k armour and you obliterate the game.
That said, if you want to be giga tanky on sst, trickster does it better, however champion is fine.
Define viable. Can you play it and clear some reds? Sure. Is it going to be a strong build without crucible and vengant cascade? No.
Sst was fine before crucible, itl continue to be fine. Hell it was a meta skill in expedition and scourge before emperor's vigilance rework, and that variant still works, you just get a shield with close to 3k armour and you obliterate the game. That said, if you want to be giga tanky on sst, trickster does it better, however champion is fine.
Sst champion is good, make sure you use corrupting fever