My unpopular opinion is that a lot of people act like the game is extremely easy exclusively because of the fact that they already know everything there is to know.
As it turns out, the most overpowered thing in this game is *knowledge.* I tend to introduce this game to a lot of my friends, seeing as it's one of my favorites of all time, and watching a new player try the game for the first time... there's a whole lot of things to learn and nearly nothing to teach you, and that's where I usually see the difficulty come from. Once you know what you're doing, it gets pretty easy indeed. Not to say I don't want more difficult content, I'd personally love to see it, but I can definitely understand why we don't get a lot of these changes outside of side, optional content. New people have a LOT to learn already, so adding more difficult content for them to learn, especially when if it's something that they are forced to deal with early on, is definitely something that needs to be thought about carefully. Still, I'd love to see more base biomes and updates to the overworld and caves instead of the ocean, which are all relatively agreed upon opinions, but I think people overestimate how easy the game is because of how much we already know, and I wonder what kind of new content could be added.
Now, should new players be the only thing in mind when doing updates? Eh, definitely not. Veterans and long-term players are just as important, but at the same time, I can personally understand why they're generally going the safe route here. I hope we get more exciting permanent content outside of the ocean soon, maybe something we need to interact with more, but it needs to be careful to not just completely and utterly overwhelm everyone who doesn't already know what to do.