Even if Civ 5 was a worse game mechanically (which it used to be before BNW) I would still play it just for the quasi-historical atmosphere. The idea of playing through the eras of history is fun on its own, just for its experimental elements if anything. If you strip that out and replace it with generic sci-fi concepts, you lose a lot of the fun and are just left with the bare-bones mechanics and nothing but a few mildly interesting sci-fi themes.

I might have been interested if its backstory had at least been tied into the rest of the Civilization series, with the game representing those civs that had gotten scientific victories at the end, but it seems Firaxis went way too far out of their way to differentiate this from Alpha Centauri to the point where the backstory had absolutely nothing to do with Civ. As a result, I'm left feeling disconnected from the overall series, like I'm playing some kind of wacky mod.

If there was more of a procedural setting with an emphasis on exploration, I might have been interested in that. Say that when the world is generated, any element including the biota is generated differently, both aesthetically and mechanically, meaning you could end up on a wide series of diverse alien worlds with wildly different appearances and themes, the possibility of intelligent native alien life with different levels of development, etc. so that you basically have no idea what you're going to get (depending on how randomized your settings are), the same feeling you would get if you were actually exploring an alien world that had never been set foot on before. Instead, we're basically left with the same world over and over again with a few changes here and there based on settings. That's as boring as Earth was!