The first 2 seasons of TNG are universally regarded as the worst part of the show’s history. If you want the whole sordid story of why these seasons are such a mess, I suggest watching Chaos on the Bridge, the 1-hour documentary about the beginnings of the show.
One of the biggest problems with the first season is definitely Tasha Yar, played by Denise Crosby, who was chief of security in that season. We know very little about her, and she was one of the few characters who didn’t get a spotlight episode in the entire history of the show. This is her only spotlight, and–spoiler alert–she dies! Is it any wonder why Denise Crosby wanted to leave?
I understand the premise. Because Starfleet is a military force as well as a peacekeeping one, it would be expected that an officer would not always get a heroic exit. So giving her a tragic death is fine. But because we know so little about her, it doesn’t have the impact it should.
And then there’s the villain. See that pic above? That’s Armus, a living oil slick. It’s supposed to be a manifestation of the evils of the colony that had once lived on the planet. OK, it has a cool back story, but it looks awful. Was this the only way they could write Tasha Yar off? There’s an internet reviewer named Chuck Sonneburg, who uses the screen name SF Debris and reviewed this episode. You can find the link here, and I suggest you listen to his take. He comes with a few endings for Yar that were better than what we ended up with.
OK yes, the show did eventually fix this. First we got “Yesterday’s Enterprise”, which I will get to. And Denise Crosby gladly came back to play Sela, Tasha Yar’s Romulan daughter. (It’s complicated.) While Sela was an interesting character, Yar deserved better. It was wasted potential.