The early seasons were less serious than later ones. But overall, it did well with serious social issues and addresses some very relevant topics.
The storyline with Topah was absolutely amazing. At every step, each character was portrayed well, and respectfully. It’s rare that there is a story like that that still has conflict without having a clear villain.
The time travel episode with Gordon was also especially brutal with some great performances from everyone on screen.
There were a few misses. I found the Isaac / Doctor relationship… forced, even if it did bring us the best line in decades (“As I am incapable of stuttering, I must conclude that you heard me.”). I also don’t think I’m alone with disliking the Charlie character in season 3.