Having moved into the mid-game, I find myself in an existential and moral crisis. I joined a federation, and I had high hopes that it would be like the Federation - an enlightened group of peaceful planets that seeks out contact with new civilization in order to advance the condition of sapient life throughout the galaxy. But it turns out that my new Federation isn't like that at all.
It started out fine. Our first two members were committed pacifists. And our third believed in democracy so much that they would only go to war to liberate the oppressed. But you need four civilizations to form a Federation and our fourth was a real snake in the grass.
Fanatic xenophiles, I assumed they would want to make friends with everyone they meet and thus were unlikely to start a war. However, they apparently love aliens so much that they want them all under their rule, because every time they get to be Federation president they start a new war of conquest. And because my fate is tied in with the rest of the federation's, if they lose a war, I may potentially lose a planet, so I have to do my best to win the wars they start. It's a far cry from what I intended when I set out to play a pacifist.
That being said, I love that Stellaris is the sort of game that has that kind of complexity and conflict. I haven't yet been bored by the mid-game, and there's still plenty of peaceful stuff for me to do, even amidst all this war, so I'm looking forward to moving on to the end-game, which I understand has a few surprises in store for me.
I'm definitely getting the feeling that this is a game that I'm going to play for more than 20 hours. I want to become one of the great elder civilizations of the galaxy and see the end of the tech tree, but that's probably still a long ways away. Normally, I'd probably start getting daunted by the scope of the future in front of me (see - the anticlimactic end to my Crusader Kings 2 game), but with space it feels different. It feels less like I'm running towards a goal and more like I'm just trying to see what happens next.