1 - Johnny is a hero. One misunderstood and who looks at his own ass first, but a hero.
People have the misconception that heroes need to have messianic qualities or that they can't be horrible people.
One of the heroes of my country is a guy who got under a tank with a grenade in each hand. Heroes don't always succeed in life or end well. In fact, it is rather the opposite. At least he was trying to do something good with his music. Kerry is cool and all but he is basically Cyberpunk's Bon Jovi.
He risked his own life to save Alt twice. I remind you that normal people in Cyberpunk would stay at home crying or hire a merc.
2- Rogue really loves Johnny. Like madly, true love. Imagine how much as to embrace a digital construct of her dead ex-boyfriend knowingly and do everything he asks of her without asking. When you talk to her about him, she is always affected.
She knew that she was going to die in the Arasaka tower in Johnny's ending, thats why tells her son to stop the car and look at the stars in that last conversation because it was gonna be the last memory of his mother. It even makes me sad thinking about it.
We can discuss whether that love is deserved or not, but it is something between the two of them. She sees something in Johnny we dont.
3- As I said in another post, the causes of the explosion are not at all clear, Johnny was already outside the building. Suspicious.
The real target was the foundation of the building deep underground. Johnny tried to get the building evacuated.
Aside from saving Alt, a fact he doest hide, he did it because he was against Mikoshi's principles. He talks about this in the badlands.
4- As I understand it, your consciousnesses are merging but you are still two individual beings. Johnny lowers his defenses when he sees that you are a good person who can be trusted. -Would you take a bullet for me?