Torkoal isn’t as bad as you say. It gets both spin and rocks. It is physically impervious and the tech is to actually use its stronger attacks and try Body Press. Torkoal actually 1v1s Tyranitar which is comical. It beats Kingambit unless Gambit is 5 fallen. It’s good into Iron Valiant as well. With Tera, you can use Torkoal to check pretty much any physical threat you need it to.Rain and sun are too fishy in general, you've got too many outs vs them via Tera, strong speed control options like Deo-S, Dragapult, Booster Valiant, etc. and whatever benefits Pelipper and Torkoal do bring don't outway the cons of using a generally useless mon. I feel Sand doesn't have this issue to the same extent since both Hippo / Tar pack more utility in the metagame than either Torkoal or Pelipper, which are both Rocks weak, locked to a bad item, and more limited in what they can reasonably deal with. Sun is espicially fishy since you are buffing the opponent's paradox mons like Raging Bolt and Gouging Fire, making them significantly more difficult to deal with. An issue I personally have is that these styles don't really have room for good pivots. Really the best you are getting is something like Eject button Hat or Eject button Treads, which are solid but 1 time use and not enough.
For sun-specific pivots, they do exist. For slow pivots there is Landorus-T, Corviknight, Mandibuzz, Raging Bolt, and Slither Wing. For fast pivots, there is Landorus-T, Roaring Moon, Cinderace, and Slither Wing.