The last five hours took me several days, thanks to Zelda, but those five hours were densely packed. Once I got into the game, I focused on it pretty hard. The RTS mechanics are still stressing me out, but the underlying game is solid enough that I'm willing to overlook them.
Although . . .
The diplomatic victory is kind of silly. If you have positive diplomatic relations with your AI neighbors, a counter will tick up. Once it reaches a certain point, you win the game. Getting the computer to agree to peace treaties and whatnot is kind of tough, but once you do, the final victory is sudden and arbitrary.
I guess I like it for letting me sit back and build up my territory, but ultimately, it has the same fundamental problem as most other 4X diplomatic victories - NPC empires are scored like human empires, and thus have no reason to help you win the game. Thus, you either have a situation where the diplomatic victory is virtually impossible - like in Endless Space or the AI simply can't register the possibility and does nothing to stop you - like in Sins of a Solar Empire: Trinity.
The only game to ever get it right was The Last Federation. That game was centered around the idea of diplomacy and though you could build and fight and research, all these things existed primarily for their broader political implications. And it's unclear to me whether it would be possible to transfer those lessons to a more traditional 4X game without also turning that game on its head.
I think the issue here is that the 4X genre started as a pure war-game and then branched out. Consequently, most alternate victory conditions feel like they are short-circuiting the intended mode of play. You don't really have the same back-and-forth or multi-sided rivalry in cultural or diplomatic victories as you do with military conquest. Civilization V's cultural victory comes close, but archeologists tend to have too high an opportunity cost and are blocked by closed borders, so it's usually easier to exploit other mechanics than to engage with the whole "globe-trotting tomb raider" thing the system could potentially be.
And I think that's just another piece of evidence for the pile. Borders being closed to civilian units by default only makes sense if you view civilian units as specialized military units. Of course you wouldn't let even a friendly nation's tanks and/or super star-destroyers pass through your territory unless you were close military allies, but their merchants, priests, and archeologists?
It's a flaw in the genre, this open assumption of hostility. If we really want satisfying non-military victory conditions, we have to acknowledge the elephant in the room - military conflict is literally the only field of endeavor where we humans don't at least pretend to help each other out. I mean, sometime commerce can be a little cutthroat, but even then the idea is that each party in a trade walks away with something they consider to be more valuable than what they had before.
So no game that bases itself around the assumption of a zero-sum conflict can ever completely actualize diplomacy, trade, science, or culture. The central idea behind most of these things is that sharing and trust make both parties richer than before. Culture spreads beyond borders, scientists publish their findings, traders open new markets, and diplomacy sells the idea that more communication, more openness, and more thorough contact makes everything easier. In the real world, it is harder to contain an idea than it is to spread it, and ultimately, the attempts of the powerful to do so can lead to poverty, ignorance, and possibly even war.
Although, how do you distill something like that into a concept as concrete as "victory?" None of that good stuff I mentioned ever has an end. We're never going to know so much about the universe that we just decide to stop performing science. We're never going to be so rich that we decide we've run out of use for commerce. It might be possible to unify the world diplomatically, but if it happens, it's not going to look like one nation overcoming all the others. In truth, a "diplomatic victory" is going to be virtually indistinguishable from a"diplomatic loss." The "world leader" must sometimes be a "world follower" or that's just conquest by another name.
I don't have any solutions so I guess I can't be too hard on Sins of a Solar Empire: Trinity. The game saying "well, you've been doing a lot of diplomacy, so I guess we'll let you win now" is not an ideal way of doing things, but it does have the appeal of simply cutting the Gordian Knot. Diplomacy has no natural end, so they just imposed an artificial one. I'm not sure it "works" per se - the game suddenly cut out just as I was starting to come to terms with a galaxy at peace - but it does at least have the advantage of not drawing things out.
I don't know if I'll go for the diplomacy victory again, but luckily, that's not a decision I have to make until late game. This game has so much war and fighting, that only the truly powerful have the luxury of negotiating for something better.
I'm going to choose to believe this isn't true in the real world as well.