I too, feel disappointed about the ending but isn't that's the point?
It's just a story of a mob character that stays to be a mob character till the end.
Anything else would be too ooc for her; unless she stays longer in that world, which is not what's happening.
Of course, I do agree that Satoki deserves much better.
I love Satoki and her indecisiveness.
I don't think the whole story is that's bad; aside of the so-called heroine, the king and the knight, I believe everyone else do have a brain in them.
Guess it's my first time reading shoujo manga and think it's going to be far better without its shoujo-esque.