The "science fictional gameworld" part of my offer was the important bit. If we're just talking abstract game thing, then mechanics pretty much rule, and you might as well just make everything as simple as possible while supporting the core gameplay.
But "science fictional gameplay" implies that it's not just moving pieces on a board, or connecting Platonic shapes, or some other purely abstract play form -- the play takes place in a world
That instantly means that the shape of the world -- the structure of the setting for the gameplay -- matters. Even if it doesn't have some obvious direct impact on gameplay, it matters because it's what communicates to the player that the things they'll do are consistent with the physical organization of the world, as well as with the social (and economic) organizations of the people in that world.
And even more particularly, Limit Theory isn't just any old game; it's a game of starships and empires set in a futuristic milieu. There are stars, and planets, and nebulae; there are starships and spacedocks and ship systems. All these things combine (and will, I assume, be joined eventually by a lot more lore and artwork and objects that all work together to tell a particular kind of story about the nature of the universe in which the gameplay happens.
Which brings me (finally) to the benefits I see for a 3D map. I'm not just in favor of such a map in any game; it's foolish not to consider context. A 3D navigation and information map improves a game with the features I've described in the following ways:
- The 3D nature of the map tells players that the universe, like star systems, is a volume, not just a disk. Not every real-world thing needs to be simulated in a game (I've argued elsewhere that "plausibility" is a better standard than "realism"), but people know that space is three-dimensional, and that dimensionality is a defining characteristic of science fiction that involves space travel. A 3D map is a representation of physical space that feels more plausible for a science fiction game than a squashed 2D map.
- It's a somewhat smaller thing, but a 3D map also sends a message that the creator cares about the "feel" of the game, and that it's not all and only about pure rules-based mechanic-following. Showing that the universe has volume by representing that in the map simply feels more interesting than a map that's flattened for obvious mechanical convenience.
- A 3D map that's easy to use (which as I've suggested is a thing that can exist) is a useful selling point for a space game. A 2D map can be pretty, but a 3D map that's pretty is simply more impressive. We might not like that eye candy helps sell games, but it does.
- It's not all about "feel"; a 3D map can do a better job of showing actual distances between systems than a flattened 2D map. If some missions are timed, or certain cargos are perishable, being able to rotate a 3D map to find the shortest path can have good game-mechanical value. (Extra code could be added to a 2D map to highlight shortest routes for you, but where's the fun in that?)
Overall, maybe it's just a feeling on my part, but it comes down to: a 3D map is not that much harder to implement or use, and it's more accurate and more fun to render a 3D space in a science fiction game with a 3D model.
To close, this isn't the most important piece of design for Limit Theory. I could live with a 2D map if it means something more important gets more attention. But if we're talking about our druthers, well, there's mine.