"This show is so cynical and edgy!"
"No it's not! Did you even get the point of the show?" *references last episode*
This kind of thing comes up a lot in places like tumblr confession blogs. And I can understand the finale of the series was meant to have a hopeful message, but the thing is...
When the show was first airing, no one knew such a thing was even a possibility, and viewers had to wait a while for the finale.
No one had any idea that the characters deaths would be reversed, or that the show would end on any kind of optimistic or hopeful message.
By episode 10 it seemed like the show was ramming the darkness and utter hopelessness as hard as it could go, so to watch that episode when it aired and have to wait like... a month for the resolution is a very different experience than having so little time to dwell on events when you can just pop in the next episode two seconds later.
It did seem kind of obvious that Madoka's wish would be the key to solving all of the show's conflicts, but from my point of view it still seemed like nothing but misery was on the horizon.
On a somewhat related note, people who don't think Madoka is all that dark and cynical must watch a lot of dark shows, so by comparison it must not be that big a deal. For someone like me, whose typical anime looks like this...
It's pretty dark.
Having the main characters die all over the place, doomed to die no matter what they do and having the whole world exist just to screw them over for ten episodes, is pretty dark for this genre. I'm not gonna argue the ending but I can agree that it attempted to express the idea that hope can win in the end, no matter how terrible things get.
So yea, the impression is a lot stronger if you watched the show airing and let each episode sink in for a week at a time, rather than marathon it all in one go.