Continuity mistake: In the episode "The Web", the tarantula has Cheetor trapped in a stasus web that sucks the energy from his life force and is viewed on a machine. A couple of scenes later, Cheetors life bars are very low on the machine, but when Rattrap comes to save him, the bars are full again, although Cheetor is still dying.
Continuity mistake: At the very end all the Maximals are together watching the mountain explode, but when Primal yells "Beast Wars" the camera quickly zooms away and only he and Dinobot are standing there, the others have disappeared.
Chosen answer: Terrorsaur was probably removed because his character was far overshadowed by Tarantulas. Both characters were treacherous and backstabbing towards Megatron, but it wouldn't have made sense to have two characters who served the same purpose, story-wise. Scorponok was removed because they wanted to introduce Quickstrike, and it wouldn't have made sense to have two scorpion characters on the show.