Dresden Files didn't die because they made mistakes or because of ratings. Do some quick research and you'll find some interesting facts and rumors.
First of all there's an often repeated rumor that's said to have some serious credibility, apparently the head of sci-fi at the time who is the lady we can thank for all the stupid wrestling shows on sci-fi, sorry syfy, right now, came to the studio and tried to change the show to be more mainstream.
The people working on the show told her to screw, and she got pissed and the show was cancelled after its first season citing "lack of ratings" and sci-fi refused to offer any comments or explanations beyond wanting shows that targeted a larger female audience.
So let's look at some facts shall we.
#1: Dresden Files was not hurting for ratings, it beat Battlestar Galactica 2 or 3 times actually.
#2: Dresden Files was gathering an enormous female following, once again even larger than the one Battlestar Galactica boasted.
#3: Ms. Hissy Fit wrestling fan was never a fan of sci-fi, she was just a suit.
#4: She had problems with lots of other people at the network who couldn't stand her.
#5: Sci-fi changed their name to Syfy which just shows they can't be trusted. (Ok maybe that's not a real fact but it should be)
What we have here is a clear case of some suit's ego winning out. Why else would they cancel a highly rated show that was bringing in the audience they claimed to want to bring in? Don't take my word for it though, go search and see for yourself. Syfy needs to get back to its roots fast because the real sci-fi fans are turning on them.