I am in very much in favor of flaws being introduced into D&D. Unearthed Arcana did a nice introduction to flaws, but the class, and now race, specific flaws are a much needed improvement. I see flaws as a way to help flesh out a character. To give ideas for how your character would act under certain situations. And to give non-humans a chance to get more than one feat at first level.
No one in my campaign has opted to take any flaws. I think the reason is that it is the first time that most of them have played 3.5 and they are trying to keep the new material to a minimum. I am just waiting for monk flaws. I am wanting to play a monk for the next campaign, but I want to see what monk specific flaws there can be. I am waiting patiently and hoping the others in my campaign take a flaw or two.
Jason