What I meant by my comment was that many people were complaining about TSL's technical limitations (i.e. low polygon counts, low res textures, choppy animations, high school writing, etc.) as though that was an art direction issue. Technical complexity and art direction are two entirely different things.
That said, I am not a huge fan of TSL's art direction either. As Baggins pointed out, the character designs tend to lean a little TOO far toward the anime-inspired end for my liking. (Even the SLIGHTEST lean toward anime is too much for my liking.) I wouldn't mind if Telltale took a slightly cartoonish approach with their characters, but I wouldn't want it as exaggerated as BttF. I wouldn't want the gritty look of Jurassic Park either, though. The JP character designs look very bland and cookie-cutter to me, kinda like Dragon Age Origins characters.
In my opinion, there is a very simple formula that Telltale should try to duplicate. Simply look at the cutscene paintings from KQ5, and turn them into 3D characters and settings. That style should be mimicked as closely as humanly possible. Sierra never surpassed it, and Telltale doesn't have the skills to successfully fuck with it.