Sasuke has always been a bad person, but what I think there is a difference between a bad person and a bad character.
We know Sasuke is an introvert, a loner, and a down right pratically emo kind of guy. That was never the problem with him. In fact, loved his character like this, but Sasuke was turned into a bad character simply for the sake of pairing choice.
Like you said, they pushed Sasuke to Sakura not because they made sense as a couple, but because they wanted Sakura out of the way for NH. So they threw away Sasuke as a character and for a brief moment all of a sudden made him care about Sakura, love her, and become open about feelings just long enough to put them together...and then turned him back into an introvert once it is all said and done.
Sorry, Sasuke, we are only going to temporarily give you feelings and emotions until you produce a kids and then you are back into an introvert. That is horrible story writing and how he became a bad character. You don't just randomly give a character an emotion response when in reality he has none just to make a story point and then forget about it.
Sasuke was always a bad person...and we kind of liked that about him. He was edgy and that is fine.
What is not fine is when they turn Sasuke into an all of a sudden extrovert just long enough to become a kid and then back into his old introvert self as soon as the baby is born without any explanation. That kitten is just bad writing.
It's like Superman and kryptonite where the degree of power changes based on story. A whole man made of kryptonite and Superman powers through it defeating the enemy before blacking out, but then in the next story is immediatly paralyzed by a small tiny ring with a kryptonite stone.That's bad writing.