Fox didn't pre-emt the show the local channels did and there's no proof that airing the show out of order hurt it, if anything the premise hurt the show more than anything else.
The Firefly DVD sold so well it was in the top 100 at Amazon for sales. That's pretty good for a TV show with a flawed premise.
Whedon did a great job of creating an ensemble cast where every character had a fleshed-out personality. There were no cardboard characters or stereotypes. This is not easy to do, and it's great to watch the result.