Sebastian:
You hit it right on the nail. Of course it is. We write in order to satisfy ourselves and others.
Exactly--because if the writer doesn't find the story interesting, stimulating and/or arousing him/herself, how can he/she reasonably expect others to react to it all that positively?
OTOH an author should be open to readers' suggestions and constructive criticism (RE plot and characterization), I've occasionally made comments on other writers' stories (especially if they're multi-part ones or part of a series) that have apparently influenced parts of future stories.
Ultimately though, the author will of course be the one to decide how his/her story line will develop

... --C.K.