The change in Go is that professionals now play more AI-like stuff, basically the same opening moves, and that's fairly boring to watch. It's the best sequences of moves we have so far, but also everyone knows them and isn't interested.

Another change is that territory is more valued than influence now, which too makes games less fun to watch, at least in my experience. To my knowledge, Shibano Toramaru, professional Go player, used to play highly focused on influence, and his games were very interesting to watch; it was just spectacular. But after AlphaGo came he converted to focus on territory like everyone else, only occasionally letting his beast out. But I watched only a few videos on him so don't take my word; it's just my impression.