He did savagely beat her. And was it the owl's henchmen who shot her? Either them or Ock's henchmen. I agree, Cat should not easily forgive him.The conflict between SpOck and Cat would be much more explosive, seeing as how she's still alive, he stole her on again off again boyfriend's body, and there's no denying that he savagely beat her with the intention of murder.
Thing is, if this is a redemption story then its either about forgive and forget OR its about Ock paying for his sins. At least thats the way I look at it, with my christian background. It seems very unlikely that anyone would forgive Ock, let alone forget about all the things he has done. So, for me, the only path to true redemption for him is for him to pay the price. Maybe Peter takes over his body and Ock "dies" for real. That would complete the process begun by his promising to live up to Pete's mantra, saving the girl, etc.
Ock just cannot do enough good to balance the scales, not when you consider things like the death of Captain Stacy. And killing Peter Parker of course. There has to be a price.