Get used to it, the photo quality on Win10 is complete BS (compared to what it was), but it's still...something, I mean the pictures do their job. Just wait for an update.
As for other apps, I think they give the same quality. I've tried 360 camera, and it's even worse.
I use Lumia Camera on my Lumia 1020 mounting Windows 10, and the app does a way greater job, just like prior to the update, than the default camera app.
So I firmly believe this is an app matter or, more specifically, an algorithm matter