Do you like Harry Potter, the character?
Not my favorite character, but I suspect whatever comes after this has more to do with the Wizarding community as a whole than just him.
Because say what you will about Snape, Harry might not have been able to defeat Voldemort had Snape not acted on Dumbledore's orders after his death.
Oh, how I love being correct. Cool, so just give Snape all the credit. After all he was the one who killed Voldemort. Oop wait nvm, he was too busy being dead. And it's not at all like the trio could've found another way to destroy the horcruxes. Like they were so incompetent that they destroyed 5 horcruxes without his help.
Also, he became Headmaster. While his reputation was in ruins, he took that place to protect the students. He might not have been able to keep the same order (after all, Death Eaters took over and he had to play the role) but I'm sure if one of the true Death Eaters became the head of school, the situation would be a lot worse.
"The longer Harry looked at Neville, the worse he appeared: One of his eyes was swollen yellow and purple, there were gouge marks on his face, and his general air of unkemptness suggested that he had been living rough." "'What? This?' Neville dismissed his injuries with a shake of the head. 'This is nothing, Seamus is worse. You’ll see.'" "'We’re supposed to practice the Cruciatus Curse on people who’ve earned detentions'" "'Yeah,' said Neville. 'That’s how I got this one,' he pointed at a particularly deep gash in his cheek, 'I refused to do it.'" "'I got this one,' he indicated another slash to his face, 'for asking how much Muggle blood she and her brother have got.'" "'Michael Corner went and got caught releasing a first-year they’d chained up, and they tortured him pretty badly.'" "Seamus Finnigan, whom Harry had not recognized until he spoke: Seamus’ face was bruised and puffy."
You're right. It totally could've been worse. Voldemort could've made Snape minister.
Hogwarts wouldn't be a place where students felt safe anymore.
I'm sure they felt really safe being beaten to death.
Also, that reminds me, you might be adding stuff to Snape's mistakes' list that he was forced to do since he had to maintain the double agent identity. We have been highlighting on his darkness and cruelty, but he still had good in him, till the end.
Never mind, I guess he's excused from all the bullying, torture, and overall evilness. The best thing he could've done for Harry was died; I'll give him that one for sure.
Overall, I just don't think he made up for any of his mistakes. Doing one good thing does not erase all the bad, especially if the bad is happening coincidingly with the one attempt at redemption or whatever that lame excuse for a good deed was.