The reason why there was no happy ending for the Magical Girls(until Madoka made her wish) was because of Kyubey. Those girls HAD to die for the universe to not die. It would be useless for Kyubey to turn them into Magical Girls if they did never ever die or turn to witches and they had to be defeated by other Magical Girls again so Kyubey can gather the energy to counteract Entropy. This forms the endless cycle that Kyubey wanted/needed. The girls had no other chance than to die. Yeah, it's a bit cruel.

At least that's what I understood. So I can't really understand why you say that's something negative about the show. A happy ending for every Magical Girl would have made no sense for Kyubey and he wouldn't have turned them into Magical Girls in the first place. Please correct me if I'm wrong.

Excuse my not so perfect English, I'm from Austria.