Well, I think there was too much emphasis on Bean, every scene was about how cute he was or how he was taking over the scene. They weren't trying to blend him into the story. At least, that's how I remember it. And that's usually why new characters don't work on TV shows.
Yeah, it is amazing how well Bunsen and Beaker fit in to the group, and still stayed true to their adult personalities. I actually like Baby Bunsen better than adult Bunsen lol.