That's an optimistic way of seeing things, I suppose. I struggle to see this though, especially after how even this new concerned version of Sensei risked Miku's life last update. While saying stuff like this: 
Sensei is probably the shittiest person in this game, imo.
		
 
		
	 
Understanding someone does not mean justiying  them, I also think his actions through the game so far makes him probably the shittiest person in the game, and even if I talk about the moments when I think he has shown genuine care about his students, I know there have also been times when for no apparent reason he has been a complete abuser, and that contradicts part of my reasoning about him.
I just like to think about what makes people be the way they are, I'm not a religious person, but I often ask myself if a god truly exists and he's going to judge us in the end of times, how would he judge us?
For us human I think acts are the easiest way of judging someone, but I like to think that there's more behind that, that good people makes truly bad acts, bad people makes truly good acts.
So I'm not going to say post resets Sensei is a good guy, in fact I would say the opposite, but I think deep inside him, he's a good person that has been through so much shit and also a god took away his good emotions, making him the way he is.
Or maybe he's just a shit person, I don't know, maybe I'm just wrong xD.
	
		
	
	
		
		
			Actually this talk about Sensei reminded me that one thing that seems to be in pre resets Sensei's favor when it comes to shittiness, is that he didn't seem to want to fuck Ayane pre resets:
So, I think it's fair to consider current Sensei more of a slut and a cheater, than Pre Resets Sensei.
He didn't seem to be someone who'd cheat on Maya, albeit the Yumi detention stuff could imply otherwise, and he likely was cheating on Niki with Sekai, but that's a little hard to judge fairly considering his relationship with Sekai, was, well.. a special case.
		
 
		
	 
Ohh adding this to my whole speech about Sensei's nature.
Also I've never thought that the "creepy detentions" Sensei used to give Yumi were really something impliying molesting her, I think that if it was the case, Yumi would treat Sensei in a very different way, I think that Selebus wrote that on purpose to make us doubt about Sensei's past and him being good or not. My guess is that he wanted to help Yumi, he saw something in her that remembered about himself and was triying to help her going throught that.
The thing that concerned me the most is how his relationship with Maya was, because she was very young, but, and again it's me being optimistic, I think they two shared a special bond knowing they both were abused by a close person during their childhood, or maybe it's a total different shit, this part I think is still hard to say.