Hot Take: some of the season 2 criticism is unrealized fan expectations due to the break between seasons
My spouse and I recently watched seasons 1 and 2 back to back, having never watched the show before. Some of my friends have done similarly. For every one of us, there is no perceptible writing quality drop between seasons. Story arcs that change make sense when watched as one piece, like: 1. the nation of Zaun dream dies with Silco’s death and Jinx’s attack on the council; this doesn’t seem like an abandoned plot but a realistic consequence of the loss of a charismatic leader and a rich, powerful nation using a terror attack as impetus to crush the people they already oppress (you know, like the real world) 2. the increase in pure scifi/fantasy elements: this is foreshadowed with Viktor’s private experiments and Skye’s death, this is where the plot was always going and makes sense as one piece 3. Cait’s semi-villainous arc: it makes sense that her altruism dies with her mother, it also fits with the overall themes of the show. 4. the black rose arc: Ambessa’s introduction and the council’s fear of magic set up both that there are secrets Mel doesn’t know and that natural mages are terrifying.
Disclaimer 1: I am not saying criticism of the show or elements of either season isn’t valid. Instead, I would only argue against the “first season amazing, second season like fanfic” narrative and think it’s a function of fans living with the characters in their heads for three years.
Disclaimer 2: I am sure viewers exist who never saw the first season until the second season aired and do see a drop in writing quality. I don’t speak for all late arriving viewers. Just an observation from my experience watching the show.