Dork Age: The later part of the ABC era, trying to catch up with Technology Marches On involving the on-screen scoreboards and first-down lines that came with it; and for one season, oddball team nicknames were used on the scoreboard rather than the cities (i.e., "Vikes" and "Pack" instead of "MIN and GB") to provide a "hipper", more informal feel for the the game.
A lesser known variant: In 1975, Alex Karras (filling in for the then-departed Don Meridith) quipped that Raiders lineman Otis Sistrunk was from "The University of Mars" (Sistrunk's school was listed as "U.S. Mars" which stood for "US Marines"). From then on, the Raiders' changed Sistrunk's college in their official literature from "US Mars" or "none" to "U. of Mars".
He wasn't far off: Mars was named for the Roman god of war.
Never Live It Down/N-Word Privileges: Howard Cosell's infamous referral to Redskins' receiver Alvin Garrett, who is black, as "that little monkey".note It's highly unlikely that Cosell, known for his vocal support of civil rights, intended a racial slur. "Little monkey" was a common nickname used by Jewish parents for little children (given that Garrett was younger than Cosell by nearly 40 years, Cosell's use of the epithet is somewhat understandable). He reportedly used it for his own grandchildren. Cosell had used it for another player in 1973 with no consequences, and Garrett himself took no offense. The incident eventually led to Cosell's departure from the crew.
Break the Haughty: The subsequent vilification this incident sparked (not helped by the fact that Cosell was rather disliked by his peers).
The Scrappy: Dennis Miller - for every fan who loved his out-there metaphors and similes, there were nine more who just wanted him to shut up.
Seinfeld Is Unfunny: Many of the standard parts of sports broadcasting - heavy use of on-screen graphics and instant replay, multiple camera angles - were innovated by MNF.