The Television Specials That Might Have Been Commentary By all appearances, the big broadcast networks jumped on every reunion special they were pitched for this year's May ratings sweeps, which begin Thursday. But gossip has it that the nets were, in fact, selective, rejecting after careful deliberation a stack of proposals, including: "TV's All-Time Stinkers and Jaw-Dropping Disasters." A cavalcade of megaton bombs through the years, including "Supertrain," "Pink Lady ... and Jeff," "Mr. T and Tina," "Life With Lucy," "The Brian Benben Show," "Central Park West," "Platypus Man," "Wind on the Water," "The Secret Diary of Desmond Pfeiffer" and "Woops!" "TV's Taboo Smashers." A survey of breakthrough moments in TV history, including Archie Bunker's flushing "terlet," Maude Findlay calling her husband a son of a female dog, and "NYPD Blue's" historic baring of male buttocks. "The 'Mary' Reunion." Regrouping the casts of Mary Tyler Moore's 1978 comedy-variety hour, which included Dick Shawn, Swoosie Kurtz, Michael Keaton and David Letterman; her revamped 1979 comedy-variety hour, with Keaton, Dody Goodman and Joyce Van Patten; her 1985 newspaper sitcom, with Katey Sagal and James Farentino; and her 1995 newspaper drama, with Joe Morton, Kelli Williams and Gregory Harrison. "20 Years of Must-Flee TV." Restocking NBC's vaunted Thursday-night lineup hasn't been easy, as evidenced by this retrospective of "Madman of the People," "The Single Guy," "Union Square," "Inside Schwartz" and other losers. "Look What's Talking." An hour's worth of clips from series that featured animals with a magical gift of gab, including "Mr.