I posted it on the previous page but I remember that Brisson said that it was the X-Men editor's idea to bring her back and he had to make it work, I'm not sure why you think she hated him, she basically told him that it was really difficult for her to stay away from him (and again she wasn't even talking to her Logan) but for now she had to do it in order to basically rebuild her life. It's in a way similar to how she she couldn't marry Logan in the past because of her honor, it was something really difficult for her:
They shouldn't talk like they used to, at least not right now, it would make no sense to me and if Mariko wanted to ignore him for the rest of her life, she would have refused OML's last request. For once a writer didn't treat death and resurrection like a joke, and basically had a character saying she needs time on her own to figure things out away from anything from her past, basically setting up an emotional journey where the character will surely come out better out of it, I dunno for me that's the way to do it. The problem is that for now, she's nowhere to be seen but with any luck she will appear during the Percy's run where she will get some much needed character development.
Brisson didn't change her characterization he basically followed up on what happened the last time we saw her while she was in Hell for years and after Satan forced her to torture Logan. Even when Logan wanted to rescue her, she refused saying she wasn't worthy, that she deserved what she got, she told him to live his life, I mean she even said that someday if she had another chance in another life, she would try to redeem herself.
How does it destabilize things with Amiko? Amiko is an adult now, she's living her life with her "mother" Yukio and with Logan when he can come to see her, even though I like the Amiko/Mariko relationship in the past I could understand if Mariko isn't ready to see them again so soon.
A mini-series or just and arc in the Wolverine series could be a good way to explore the consequences of this storyline especially when it comes to the relationship between Mariko, Logan, Yukio and Amiko.
Dying and coming back to life after so many years should be a traumatic event, an horrific experience that changes a character in my opinion. Because a lot of writers treated this subject like a joke in recent years, doesn't mean every writers should do the same. Mutants may be "immortal" now but I'm not sure if many of them remember their death or their stay in the afterlife, Hickman slightly touched upon this subject by saying that they have plans in place to deal with the emotional trauma that come with coming back to life years after someone died.
For someone like Wolverine, coming back from the dead it's something he's used to, even though each time it's a painful experience, that's basically his trademark, but for someone like Mariko or even other characters who don't possess any healing factor/immortality? Nope that should change the way they look at their life and at the world especially after so many years away in my opinion.
Of course if that was up to me, some characters like Mariko, Mar-Vell, Gwen Stacy or Uncle Ben should stay/should have stayed dead, with that said, for a long time I thought Bucky should have stayed dead too but damn what Brubaker did with him when he brought him back was just amazing.