As a random aside, it occurs to me that, from an outside perspective (Homura's in particular), Sabrina kind of does fit into the whole "I wish everything could be fixed" role for all of the people Madoka knows/knew on a personal level (and more besides).
For Homura, Sabrina showed up out of nowhere, knew exactly what was going on, what Homura had been through, pledged to help and support her, acted as a vital translator/mediator between her and everyone else (thus preventing her making an enemy out of everyone but Madoka through diplomacy failures and an inability to social), and has the ability to actually stand up to Walpurgisnacht (and kill it). The emotional support she offers to Homura is a big deal, too--it's something she's basically not had since her first loop. And let's not forget that Sabrina's power basically offers the ultimate incentive for magical girls all over to come help fight Walpurgisnacht, meaning that, even putting Sabrina's sheer power aside, Homura has good reason to expect that she'll have a small army of meguca backing her up against Walpurgisnacht this time--giving her more reason to hope than she's had in ages. Ironically, Sabrina often acts like an older sister or mother figure to Homura (making sure she eats better and more often, making sure she gets enough sleep, making sure she interacts with friends more often, making sure she knows that Sabrina supports her and has faith in her, etc)--despite (probably) being the magical Wish-child of Madoka and Homura.
For Mami, Sabrina showed up out of nowhere, was friendly to her, supportive of her, understood her loneliness and promised to stay with her...and did. She revealed Kyubey for the false friend that he is, as well as the truth about Soul Gems, but has remained her rock of stability and comfort throughout. She continually shows that she's fine with Mami acting clingy (as a result of her trauma) and isn't driven away by it. She's given Mami the physical comfort and affection she's badly craved for years, too. The positive reinforcement and praise help, too. Not only that, she's slowly working towards mending the relationships she once had with her former pupils/friends.
For Kyouko, Sabrina showed up out of nowhere, helped her adopted little sister out (and saved her from a Witch), offered to cleanse her (and Yuma's) soul gem at any time for free, bought them a bunch of food, and offered friendship, maintaining a stubborn determination to get past the 'tsun' part of Kyouko while still respecting it. All the while, making Kyouko feel less like she can only rely on herself and countering the notion that she's a purely selfish or bad person.
For Sayaka, Sabrina showed up out of nowhere, became a friend to her, and prevented things from falling apart around her. She rescued her and her parents from their burning home, then brought down the ones responsible. When Sayaka contracted out of feeling helpless and a burden, Sabrina was quick to reassure her that she would be okay and that she hadn't made some fatal or foolish mistake. She respects Sayaka's determination to be a hero, and thanks to her power, gives Sayaka the ability to afford to be a hero. Sabrina's abilities and goals offer Sayaka a way for her to reconcile her views of how the world should be (or how she should be able to act in it) and how it really is--she can acknowledge that the magical world is a very shitty place, but Sabrina offers both hope that it can get substantially better and a means to actively fight for/contribute to making that hope a reality. Oh yeah, and she facilitated healing Kyousuke's hand.
For Madoka, Sabrina showed up out of nowhere, became a friend who quickly started to mend bridges between Homura and everyone else, fought to keep everyone safe and mentally healthy, while at the same time respecting her and assuring her that she is a valuable and helpful person even without making a contract, just for being a good (normal) friend that kept them sane. Sabrina is helping Homura on many levels, but also helping to keep Madoka's friends happy and safe, reducing her own worries about the overall situation. On top of that, Sabrina actively keeps Madoka in the loop, helping her to feel like she's being included and that she's useful.
For Hitomi, Sabrina brought her into the loop (preventing her from drifting apart from the rest of her friends...or worse) regarding magic, allowing her to be a normal, supportive friend to Sayaka (and Madoka, obviously).
For Nagisa, Sabrina showed up out of nowhere when she was completely distraught and alone after her mother's death, comforting her and taking care of her while challenging anyone who marginalized her suffering. She stayed in touch, being her friend and surrogate big sister, as well as connecting her to a bunch of other nice, friendly girls that helped her feel happier and less lonely.
For Oriko and Kirika, Sabrina was a driving force behind her, Mami, and Homura closely allying together to oppose them, while at the same time a moderating force for taking them down without killing them and giving Homura the assurance that they would no longer pose an active threat. Sabrina is there to curb Oriko's extremist and fatalist tendencies, while at the same time mollifying Kirika's single-issue-obsession (by keeping Oriko safe and healthy). To the point that both of them were willing to help out in a war--Kirika even coming along directly to help fight, with Homura actually being okay with that (remarkable in itself, really).
For Masami and Hiroko, the former was healed and a dual Witchout prevented thanks to Sabrina's intervention.
For the University Group, they were in dire straits and forced to fight for their very lives against a faction that outnumbered and outgunned them (and had tons of Grief Seeds, compared to barely having any for themselves)--and then Sabrina arrives in spectacular (and terrifying) fashion with the cavalry (because, let's face it, Mami and Kirika by themselves make a terrifying team), removes the immediate threat of Seed starvation, negotiates a cease-fire, and then, when the cease-fire falls through, takes their side with a hard-carry performance, effectively dictating terms that end the conflict for good.
I wonder how Madoka will react when we tell her, one day in the future, that Sabrina came into existence because of her own (past-self's) Wish. And then call her "mom".