It would have been so much better if Kylo was written like Dennis Reynolds from IASP. if instead of him being emo they just leaned into the unhinged egomania and violent rage angle.
that's unfair to Dennis Reynolds dfljakjjkgljkg
but in a way you're right, TFA established that kyle ron may have been physically powerful, but at the end of the day he was straight up pathetic and like 90% of people could see straight through him including the people who are supposed to be on the same side as him. Kyle tries to be intimidating and assert that he is greater than Darth Vader, but he whines and throws tantrums and destroys thousands of dollars of equipment the second that things don't go his way.
TFA has set that kyle had reached a point of no return the second he killed his father, that was kyle's cemented personal decision that he was going to continue on his path of darkness and rage. but then the rest of the trilogy had him moping and being a sadboy rat about it and it was so dumb. you're right they really should've just leaned further into his corruption, just devolving further and further into unhinged rage that may appear powerful and scary, but also shows how incredibly pathetic he is inside