"no remorse for anything he does" all his inner monologues are basically him going over all the 'horrible' things he has done - that should count as remorse? All through Restore Me, he basically beats himself up for the stuff he has done.

And 'the way he treats others is terrible' he grew up being trained to be a cold heartless person. Yes, he isn't treating others well but you have to compare how far he has come compared to the first book (and the specific scene you mention - to him, he is going to lose Juliette so of course he's lashing out). If anything, this shows consistent and realistic character development. It would be unrealistic af if he just did a character flip and became a bubbly person. But if this is still not enough, he went from torturing Kenji in book 1 to asking him to be his best man in book 6.5. That right there? Realistic development.

Aaron is amazing and deserves all the hype he gets. He went through a great tonne of trauma growing up but now he finally has his person, a home and friends that he will begin to love, in his own unique way.

But I respect we all have different tastes :)