I actually don't understand the post in which you explain why you think L had to torture Misa. Sorry if I'm being annoying but I'd love to understand it. On the one hand, you say: "if he has confined her with rather normal conditions only to isolate her from the First Kira and preventing her from using her powers to kill him - that would only be a matter of time when he would’ve had to let her go, because people would’ve started to ask questions". Why? People were already asking questions - the rest of the task force. And yet, they let L keep torturing Misa in the end. How would keeping her imprisoned in normal conditions have raised more questions? It still would have been a secret imprisonment that only the task force and Watari knew about - who would have asked any questions? And you also say "If he was interrogating her in much softer conditions, there was much higher chance that with time either the First Kira will find out the way to contact the Second, or the First Kira will simply kill Misa". Why? I might be missing something but I don't really follow. How would the First Kira find a way to contact Misa in a scenario in which Misa is still imprisoned but not being as tortured as she is in canon? And if the First Kira has her real name, he can kill her anytime, whether she is imprisoned or not. How does torturing Misa stop the First Kira from killing her? Then in another post you said: "If L didn’t care about human rights, the easiest option would be simply to kill Misa and cover it up as an accident." Why would he have done that? He didn't want her dead; he wanted a confession and evidence of how the Kira killings were executed.
Nothing annoying here, I’m glad we can have a conversation.
About “people who will start asking questions”, I meant people outside the investigation. If Misa, as a public person, is missing for a long time, it would attract attention, that’s it.
“How would the First Kira find a way to contact the Second if Misa is imprisoned but not tortured?”
So, I considered her immobilisation and lack of sight part of the torture, and I was talking about that. What I was thinking is that L made these kind of arrangements for safety’s sake, because he saw Kira power evolving (I mean from a person capable of killing knowing just a name and a face to being able to kill just seeing a face), so he didn’t want any more surprises, but now I find it highly unlikely. Right now I don’t think this point matters at all.
“Why would L want to kill Misa?”
Because his life was at risk. Misa saw his face. Of course L wanted the information above all, but he could’ve killed her and continued the investigation in safer conditions. But he didn’t, even if it meant he was in danger himself.
But actually, now, when I’ve had a fresh look on Death Note events, I think there is only one point that really matters: L placed a bet on a quick confession. His primary goal was to stop two most dangerous murderers in the world. I’m not “pro-torture”, but I can clearly see how L’s actions are justified. Serial killers are not to be coddled.