Peter Parker is awesome. He appeals to people because he's relatable: he has flaws and is an everyman, but he genuinely wants to do the right thing and is able to be upbeat and heroic despite the tragedies of his life.
Doc Ock cannot hold a candle to Peter Parker. Yes, villains getting redemption is a thing. But how does Doc Ock deserve redemption? He murdered Spider-Man, then selfishly did it again while claiming that after 8 issues, he knew more about being Spider-Man than the guy who'd worn the costume for 50 years. But he's not Spider-Man, he's just a generic grimdark 90's-esque character. He kills, he makes villain quotes, and he shows hardly a speck of remorse for his past actions (missing the most essential element of an atoner character).
He's also incredibly shilled. The recaps state that Ock "might become the greatest hero of all", characters who have known Peter Parker for years are derailed so that they don't realize Ock is an impostor, and the creative team mockingly refers to Peter as "your parents' Spider-Man".
Honestly, despite Peter being one of the few Marvel characters I care about (DC fanboy here), I'm not mad that he's dead. Comic book characters die all the time. You don't see me raging at Ultimate Spider-Man either. What I hate is that he died in a way completely disrespectful to his character: a villain swaps bodies with him and he dies, with nobody any the wiser. No Heroic Sacrifice
, no last words to his family. He's just dead and nobody sheds a single tear for him. It's pure shOck value.
If Peter Parker died, then Ock transferred his mind to a clone body and appeared as a mysterious new Spider-Man (with only the Avengers and some others knowing that it wasn't the same guy under the mask and everyone else thinking it was the same Spider-Man), I probably wouldn't mind. Because it's not Spider-Man I care about. He's just a mask.
The guy I care about is Peter Parker. All my complaints? They're not because Ock is a bad Spider-Man. They're because he's a horrible Peter Parker. A mask belongs to whoever wears it at the time, but a life cannot be supplanted by another life. That's why I'll ultimately hate this arc, no matter what happens.
(By the way, if Peter had died and J.J.J. had suddenly gained spider powers and become Spider-Man, I would have loved the hell out of that story.)