I see two big problems with a television series or a movie franchise for that matter.
To do them right each book would take at least 6 or 7 episodes to do the material justice.
So if it were a large network (CBS or even the CW) which did an average 20 – 22 episodes a season you might do three or possibly four books justice.
Provided you don’t run into network big shots who need to tinker with the source material as the disaster that befell the Dresden Files has already been mentioned.
But to me the biggest problem would be who to cast in the female roles specifically Tanya and Stacia and forget about the elves who are suppose to be even more otherworldly beautiful than those two.
Let’s face it hardcore DA fans are never going to agree on the perfect choice.