Opinion about gaming in general, as an observer, and very newbie player/old fart.
Games that succeed in capturing our imaginations start with STORY. It's a must. Right now we have experimentation, and tools, and world to play with those in, but no story. Even if NPCs are implemented—without their own story, motivations, and objectives (which I see as more short term than "Story")—there's no real reason for them to be there anymore than a cow or a bear. With those animal NPCs they provide food or an element of danger, but nothing else. We don't care whether they live or die.
It actual fact we don't care care that much whether WE live or die, because there's nothing more at stake than perhaps what we're carrying. I do admittedly mostly play creative, because I have a project I want to finish. Though I have started another Survival Game, and 2 hours in I'm already getting bored. I don't do violent games, one because they don't appeal to me, and two because at my age my reaction time sucks. (I'm older than my picture. 
) But I know what a good story does and how much I enjoy that.
Objectives or quests are a good start, so I agree with @sgeronimo on that observation. I also agree with @ArticuKitsu that we're in alpha, and there has been and will be a progression. That said, I don't think this game was or is being developed with any kind of story arc in mind. That's a shame, but I understand that a tiny crew can't do everything. And they'd need actual good writers with demonstrated ability to write adventure, action, gut-wrenching emotional stories—not amateurs, not hacks. So in the future, players are going to need to step in and write some GOOD stories to play and share, and there will need to be a way to implement this option in the game. Yes, that almost contradicts what I said about amateur hacks, but it's a place to start, and people will be vocal about what's good, or not.
I know nothing about how Minecraft works other than I've watched a bit of it*. I know that different ModPacks do in include some kind of story or quest arc. Though, that wouldn't be enough, in my opinion, to keep people interested except maybe people who've played and enjoyed that type of game play. It needs MORE.
A big story. Of all the stuff I've watched lately, Horizon Zero Dawn was the most satisfying story. (It didn't hurt that it is breathtakingly beautiful. Also violent—though it's very hard to find good, immersive, story-rich games that aren't. Again, I just watched.) But Rising World has the potential to be beautiful too. It isn't quite yet. (The mountains! Eeek!)
So yeah, early days, and things are coming along. I'm still a fan, and I still enjoy the creative building play. Not sure for how long. This began for me as a test to see what I could do with it.
I'll be watching to see if the ability to create a story arc that could be played singularly or in groups will ever take shape and be implemented. That could be exciting indeed, and would bring out droves of folks who think they could write a great story (think: homebrew D&D) in fact you could port over your rpg stories you already created, though maybe you'd have to dumb down all those arcane rules!
*I know a LOT pf players came from Minecraft. That I didn't I really believe is an advantage in playing this game.
