TV Tropes defines the Firefly Effect as a hesitancy to commit to a show since it may be canceled. I would say that it's more of a James Dean effect: when something dies early, it's much harder to see the intrinsic flaws.
The martyred Firefly is infinitely better than the successful alternate universe Firefly that went on for three seasons. In a single season, nonsense and contradictions have little time to accumulate. The super fans of the Star Trek series, on the other hand, could talk about inconsistencies for hours.
The thing that particularly irritates me is the Reavers. Space Pirates aren't practical in the first place, and Zombie Space Pirates couldn't maintain a space ship for very long, not to mention taking over other ships and eating their crew.