Well, ABF, I hope you're happy.

[A Black Falcon]

In the end, nothing whatsoever has changed for them. They go right back to being a happy, laughing group of friends as if nothing at all had happened. That's the very definition of a slice-of-life ending.

Um, no... a LOT has changed for them! Kanata is now quite good at playing music and has changed as a person somewhat (perhaps a little more mature? She did go and fight after all, even some of the other characters weren't sure if she could...), Noel has at least partially gotten past some severe trauma from her past, Rio had to give up on some of her dreams for the good of her country, etc... I don't think at all that just because they ended with a happy scene that nothing changed. It's not really true.

Also, I don't think I'd call anything with this much drama and sadness just a slice-of-life show...

It's revealed she had a hand in it, she freaks out, eventually Felicia tells her that it's okay and not her fault because Hopkins just used her. Then it's all forgotten. Noel never once has to face the children who were affected by it or anyone else for that matter. At the end of episode 12 she's just as happy and care-free as the others. Again, as if nothing at all had happened to her.

That's wrong though. Did you really miss the scenes showing Aisha with the disease? She had actually gotten it herself, but survived... and she forgave Noel. That was a vital part in getting Noel to be able to go and fight to stop the war, and a great scene...

Also the woman from the orphanage (I forget her name) is raising a bunch of children whose parents died of the disease and surely knows of many people who died of it because the affected villages seem to have been near the area the show is set in, and she forgives Noel too... you're just wrong.

As for the ending, they wanted to end with a happy scene to show that this show ultimately is upbeat and not sad, despite the many sad events of the show itself. I like that about it, myself.

And that's why the ending fails.

It's a perfectly reasonable ending style that has been done many times. I thought it worked just fine.

It's that's all it'll ever be.

And what's wrong with that? They must explain every detail of you are not satisfied? Man you must have hated Haibane Renmei... (which, remember, is my second favorite anime ever)