During my survey/exploration playthrough, I couldn't help but notice how beautiful some of the Gas Giants in the Core Worlds are. Their colours are vibrant and their atmospheres give them "individuality".
In contrast, Gas Giants outside the Core Worlds are very uniform in appearance, apart from their size.
Why not increase the range of possible appearances when the world is being generated? Part of the joy of exploration is sometimes finding a unique looking planet.
I noticed this the most with Gas Giants, but I'm guessing that my suggestion could be applied more universally to other planet types as well, especially those with atmospheres.
Edit: Good examples would be Chaxiraxi, Chijoraji and Melikah.