Diesel 10 only appeared on one episode and the movie that does not add any recognition to the series. Your statement on movie villains being more evil is illogical since the Thomas and friends series is known for its episodic series.
Just being more evil doesn't automatically make them the main villain, those who have the most effect is regardless if they appear the most or not. Ex: Ozai is not shown the most but has the most effect on the plot with everyone answering him.
Please stop messing with the villain roles of certain characters such as both Makuu & Janja from Disney's The Lion Guard because you're upsetting all the other users & readers alike. It's not funny & it's not cute.