I watched the first season in late 2015 (I wrote about it here) and it took me a year to watch the second season after it finished airing. Second season still follows the formula of the first season, which I find only so so at best, which makes it even worse than the first season.
Half of this season is so boring as it is about Karasuno's training camp where winning or losing makes no difference. Anyway they keep losing their matches as their players are still struggling to learn new skills so that they can overcome Aoba Johsai when they meet at the next competition. The action only begins formally at the Spring tournament in the second half of the season. Unlike the first season, I find the matches in the second season boring. There is nothing exciting, touching, or dramatic that makes me want to keep on watching the next episode. The only touching moment in this season is the match vs Wakunan when Daichi was out because of injury and Ennoshita and Yamaguchi get more change to shine. Karasuno gets a new manager, Yachi, and I am glad that she plays a greater role than Karasuno benchwarmers. Shimizu also gets more lines at this recruitment period.
Second season also still follows the same character development that the antagonists are likeable and make viewers can root for them. The schools at the training camp are more like rivals than enemies and everyone helps one another to improve. Although based on the story, it kinda makes sense since Karasuno is not from Tokyo so they can only formally compete if everyone gets into the national championship.
At the same time, a lot of characters are still being underused even in this second season. While I like Ennoshita and Yamaguchi get more screen time, I think it is stupid to 'force' to make use of the substitute only when the main players gets injured. For a sports story, I expect something more strategical in making use of the substitute like when they use Sugawara to have a gameplay with 2 setters.