So I was going out loot hunting when I realized that the only planets I can realistically go to for the best results and for any kind of a decent fight are lava planets.
I recently discovered this mod. It's basically a standalone difficulty-changing-only version of the Universe Generation Overhaul mod that my friend made. In Vanilla, everything is very linear in terms of what planets are good for what. This mod basically shakes things up by making it so that it's a lot more varied. You can find any type of planet (besides starters, those are left alone for obvious reasons) with a range of difficulty from 2-10 instead of the vanilla 2-6.5, such as a tier 10 radiation planet or a tier 2 fiery planet! It gives incentive to explore all planets for more than just places to build a base, more challenge for those that like a good fight, more progression, more to do really.
As for how it affects what is currently already in place, it doesn't. It only affects what is newly generated. In other words, players won't find that their favorite low tier home planet has become a brutal tier 10 with monsters ripping their face off the moment they walk out of their base :P If uninstalled, the planets generated while the mod was active will remain as they are, but that is all. It's also not listed in the description but the loot does scale with the difficulty as well such as tier 9 daggers, guns, etc. If there are any concerns or questions about it, I'll answer as best I can and if I can't, I can ask the author directly since he's an old friend of mine.