The execution of Anakin's backstory left to be desired. But it WAS convincing. It made a lot of sense. It might have had clunky writing and acting, but the fundamentals absolutely work. His fear of losing loved ones was played well with his mother, the fact that his transgression of the jedi code forced him to have only one ally, the chancellor, he turned into a mass murderer because he felt cornered. Palpatine played his anxiety well. Poor execution, obviously, but I still can relate to what happened and I think it was decent.
Kylo is literally a piss baby. Yes they can make anything out of him, in the future, with more info, but right now, he is a little whiny brat that killed his father and was "waiting a long time for this".
Vader had nothing to go back to, if he did things would be entirely different (and we know that with his interaction with Luke once he learns the truth).
Kylo had everything. Humanity, family, love, legacy, even power (as son of Leia). It's going to be pretty hard for them to make a 12 years old turning evil feel intense.
The fact that he was so torn in this movie also means that whichever motivation he had, was absolutely not solid conviction, which means it wasn't justified to be that evil in the first place.
The only thing they can do, is emphasize how Snoke got into his head and made him a puppet.