I asked Carol-Lynn Parente, the executive producer of "Sesame Street," how exactly the first episodes were unsuitable for toddlers in 2007. She told me about Alistair Cookie and the parody "Monsterpiece Theater." Alistair Cookie, played by Cookie Monster, used to appear with a pipe, which he later gobbled. According to Parente, "That modeled the wrong behavior" -- smoking, eating pipes -- "so we reshot those scenes without the pipe, and then we dropped the parody altogether."
Which brought Parente to a feature of "Sesame Street" that had not been reconstructed: the chronically mood-disordered Oscar the Grouch. On the first episode, Oscar seems irredeemably miserable -- hypersensitive, sarcastic, misanthropic. (Bert, too, is described as grouchy; none of the characters, in fact, is especially sunshiney except maybe Ernie, who also seems slow.) "We might not be able to create a character like Oscar now," she said.