It has a fair amount of things slowking g doesn't though like being a fast (121 speed is still very good mind you) nasty plot and taunt regen user, not to mention as a pivot its role is to keep momentum going rather than start it unlike slowking-g, who is a momentum sink who can start pivoting momentum through its slow pivoting. It can also be very good on rain teams, due to bleakwind getting boosted from rain. It has a good amount of things over slowking-g surprisingly, its just for whatever reason its being ignored. Comparing two pokemon with somewhat different roles and typings isn't necessarily a fair comparison, as neither compete for teamslots and often both end up on the kind same kinds of teams. I've seen a few very effective glowking+torn-t regen cores, and you would be surprised to see how well they preform.
My point being, torn-t still has quite a lot going for it, its just being a bit overlooked due to nerfs. Also its not fair to compare it to a slow bulky regen mon that hits hard as neither compete for team slots due to type overlap (Like where everyone had to make the choice of running skarm or corv last gen due to type overlap.) or outclass one another due to the different roles they play on a team. Just wanted to point out an oversight in your explanation