Kotal execution wasn't simplistic for me until I learned to go neutral between F1's. Even after that, there's a big difference between the un-upped 31-33's everyone does and the un-upped 42-54's that the dedicated Kotal players are doing. Once you get past that, his meta isn't all that simple at all. You gotta get in.
Jason is pretty simple, but he still has underlying tech. Goro is in Kotal's class, IMO, execution-wise. Everyone can play around with him a little and look OK with him, but its making the most of opportunities with him that gets you to his meta - and that means big damage and setting the course just right to set them up and keep him from being a target. Then, once you get to his meta - its just not that simple.
Bojutsu remains in a class by itself for execution simplicity.