What killed any chance of Karen Sisco continuing beyond one season was the repetitious trope of inept, nitwit criminals with their annoyingly silly banter--as if anyone really talks like this.
Furthermore, would any on-duty, female U. S. Marshal walk--never mind RUN around (?!)--chasing bad guys in high heels and a low-cut, cleavage-revealing top? Karen wasn't working undercover. What happened to government-mandated dress codes? The "suspension of disbelief" does have its limits.
Add to this the tiresome, done-to-death antagonism between the chief and his officers despite how successful those officers are in solving their assigned cases.
Remember how Baretta, Harry O, Kolchak, etc., never seemed to receive the respect they were due from their bosses? How many times must we hear, "Do it by-the-book or you're fired!".
Private eye Peter Gunn was persistently and unfairly criticized and second-guessed by Lieutenant Jacoby who conveniently forgot the fact that Peter Gunn saved his life on more than one occasion!
Granted, the limited 40-minute, clearly tightly-edited Sisco episode limited any chance that the scripted dialog could realistically portray how U. S. Marshals conducted their business. ACTUAL U. S. Marshals could not have been pleased with the onscreen antics.
And finally, unfortunately the name Karen itself had since become tainted due to unpredictable circumstances widely exposed via social media. Wikipedia identifies a "Karen" as "a middle-class white American woman who is perceived as entitled or excessively demanding.".
