the goal post has been shifted.
uncanny xmen and xmen 2nd series are pre--Morrsion.
Beast was always the passive character in the original 5. He was the one character that was already looking non human, his big feet, big hands and big legs made him reclusive and uncomfortable. he struggled with the changes of becoming beast and that made him dive deeper into genetic science. he was already the scientist of the 5 than the fighter, the fighter was Cyclops.Angel was the snub, Jean was the girl and Bobby was the ladies man.
Beast wanted to be a footballer but lost that dream when he was exposed as a mutant and he lived with that sadness for a long time. this is before Morrison. Beast went from a Jock to a Scientist
The origins of Beast in xmen evoltuon and xmen tas have addressed this one back story in the comics.
this is not 21 year narrative. its 60 years already told in every story.
and even if I buy your POV, There will be something called charcater devlopment in the post-morrsion era but no need for that because Beast was never just defined as a big blue fighting monster who goofed around all the time. I dont even think this defines any mutant.