Stop with this "it's optional content" nonsense. For a casual player, someone who don't have a huge amount of playtime, yeah sure it is. But for all the players that aren't pleased with Eureka, it's not optional AT ALL since it's the only new content that have at their disposal or else they must do again the same things they are already doing for weeks and months.

So, no, it's not optional. And yes, there are good reasons to not be OK with this.