There's a lot of factors to consider with something like this. What does it really add? I'm not disputing the fact that the orrery view would be immense and show things off in such an awesome way, but it has to be easily usable. There's so much data to show, so many different aspects of the game that need to be/could be visualised to give a greater experience. This is a huge technical challenge not just from a "how do we display the stellar/planetary bodies" angle, but also you have to consider what data would be relevant to explorers, what would be relevant to mission/passenger runners, combat pilots, system states, trading, and so on. There's so much data in the game, and it would be great to show it all. But each thing is a "cost" as far as development, querying the data, system resource, and also screen space. These are only the things that I can think of from the perspective of someone who doesn't really know the first thing about effective UI design, and that's already a tough set of questions to answer...
I wish I understood the finer points of UX/UI design to really engage in conversation here more... but I don't. Every so often the topic comes up internally and people think a bit more about it, but please don't hate me for setting a realistic expectation: it's an unlikely thing for us to see within the foreseeable future. Just know that I, and probably quite a few others, would love to see this feature in game. Actually, there's a lot of these kinds of features we'd love to see... hence the 'wishlist'.
A good point. I hadn't even considered this as one of the technical pitfalls.