>>279664017 (OP)
>Madoka
I think he would greatly help the girls.
If he's the MC, that means he will somehow become aware of the magical girl system. This means Kyubey wouldn't be able to prey on defenseless emotional young girls, as there would be a rational boy to oversee things. He would most likely help them identifying the scams of the incubator system.
...but in the end maybe it would actually only change something for Sayaka? Mami, Kyouko and Homura already contracted before the series begins and Madoka contracts even if she knows everything. Sayaka on the other end got fully tricked and paid the price. I think if a male MC was there to help them figure stuff out, Sayaka would probably still have contracted for Kyosuke, but this time would have done so knowing full well what was going to happen, and as such wouldn't be tormented by existential stuff when she finds out. This could actually lead to her managing to confess to Kyosuke when Hitomi leaves her a window to do so.
As to who the MC would end up with, well, i think it would most likely be Mami. Mami suffers from loneliness a lot, so this would make the most sense if we assume we must try to fix shit (but then again it wouldn't really be Madoka anymore if shit was fixed, right). Of course that's assuming the male MC somehow manages to make Mami survive.
With that, they might all be able to live to Walpurgisnacht and possibly defeat it.
Another possibility is that the male MC is actually a time traveler alongside Homura, trying to assist her in saving Madoka kind of like Mabayu in Scene 0. In this case he would probably start something with Homura, unless he already has his eyes on another girl (maybe Madoka and that's his personal reason for looping to save her).
Or maybe a harem ending somehow.
The current western fanbase would be way less cancerous that's for sure.
