I've never seen a game that used procedural generation really well though. Like using procedural generation to create mission and story as well as pretty landscapes. And have a simulation that feeds these story and missions. Sure you have every right to be skeptical, but I wouldn't write the idea off.
I know a few examples. The best one, i think, is Starbound. Even if it's 2D, you can see the possibilities growing from patch to patch. Yes, it's just bringing together a set of pre-defined pieces. Pieces like: procedural trees(different fruits, colors, blossoms, loot after harvesting), procedural monsters(shape, color, behavior, attack-styles), procedural planets(surface-color, size, materials/material-color, resources, asteroids in atmosphere, inhabitants, underground & caves, background), procedural POIs(cities, prisons, laboratories, ancient ruins, pirate bases and tons of more things to explore). And so on. Yes, there are single pieces you might remember. Like the shape of a flower, but since color and loot is different, its not the same as before. There are so much variables that the overall picture is never the same. Its not just about random generated planets with different surfaces, size and terrain color.
Space Engine is also nice. Even if there is no random generated content at all beside the planets, roids and suns, the planets look all different.
Now imagine random generated space stations(inhabited, abandoned, relic, non-human), floating ships, mining outposts, black holes, pulsars, neutron stars, comets, nebulae with different effects on your ship, pirates, faction interactions, trade-routes, laws, missions. Tons and tons of variables.
I don't think that we have to be afraid about star systems looking all the same. I think there is more potential to do something in the wrong way if the things you really DO are too similar. Think about exploration. Its not only about finding new star systems. Its also about finding new POIs in existing space. If this POIs are all the same, even if they look slightly different, exploration will be boring very soon.
I think there are three types of relevant( things you can actually interact with) POIs when you enter a new system. Mining-POIs(roids, comets, planetoids). Station-POIs(Trade, Pirates, Relics). Factions & Inhabitants(Missions and Trading).
- If there are only two types of asteroid fields, categorized by yourself in valuable and trash it does not matter if they look all different. It gets boring after you got the money you need, if the mining and the scanning is too dull and if all the mining is just about making money. There could be much more to it. For example the search for real rare materials that help you to build something special.
- The same with stations. If there are only inhabited(trading + random missions), abandoned(with some loot) and pirate stations they are very soon getting boring, too. This does not depend on the visuals.
- The same thing is happening when interacting with factions/inhabitants for trading and random missions. If there are only 5 types of random missions(bounty hunting, seek and destroy, base defence, ambush, base attack) you won't be doing them for a real long time. And if there is only trading without production chains, base building or something like this, it will be over when you have enough money, too.
So the main concern shouldn't be: Are the systems looking different enough to fill a few billions of star systems? It should be more about: are the things we can do actually deep enough to entertain us a long time when everything is procedurally generated?