There's a post from the showrunner of the ill-fated and poorly put together Green Lantern CGI series about how he feels focus groups are useless to a show and a bitter cameo with Bruce Timm, the man behind Batman the animated series.
Read the full comic here
Some posts about the comic point on that Green Lantern might have failed from bad toy sales from the live-action film. No one points out that the show itself was ugly; it was a CGI mess with Bruce Timm designs.
It's nice to get a tidbit of how a showrunner on animated series feels about focus groups, but why not just explain in detail why the show died.
Beware the Batman is going through a worse state of not cancelled, but on "permanent hiatus". WB Animation and Cartoon Network remain so not translucent as to why these series failed.
Bruce Timm changed his position in the company recently and Cartoon Network's President recently left, hopefully some sort of new era of making quality WB animated shows for Cartoon Network can come out.