|They're upset I stole this image from Wikipedia|
The plot is another Godlike Alien deus ex machina (the Organians this time), with the real highlight being the interplay between Shatner and Colicos. Organians were retconned into Enterprise (poorly), but otherwise they were only referenced in passing after this.
So by TNG, Klingons had gone shouty and brutish, while all the sneaky subtleties had gone to the Romulans and Ferengi? Going to be interesting to compare. For me anyway.