I have played Astroneer quite a bit for now and while it is great fun to play i noticed that there are several factors that make long term playing feel rather grindy and repetative. I could go the easy way and say it's just the lack of content to spend that much time on the game but i realized that there is actually enough stuff in the game already but it simply is balaced badly - as a consequence a lot of items become obsolete.
Here the RTG is a big problem. in late game it makes power management obsolete and robs the game of an fun game mechanic: solar, wind, generators and batteries suddenly become all obsolete - effectively these are 4 small, 4 medium and 1 large building that have no use. sure the RTG is supposed to be an expensive late game achievement but in my gameplay Atrox was the 3rd planet i landed on and the first one i unlocked (it made the most sense due to resources). but now unlocking everything else feels trivial and repetitive. yet it doesn't have to be this way: as it is the medium RTG beats all other medium power sources - that's bad. if it was made to be a large building however (like the large solar) with the same power output it would still be great for bases as an infinite power source but it would be difficult to transport - a big trait of all medium buildings. there should still be a (cheaper?) medium version however with significantly less output (25% of the current - exactly enough to power a large rover) that would be inferior to alternatives in raw output but an unconditional and indefinite power source.
Another issue is the (medium) Generator: i never build a single one of those. i think their niche should by to provide the highest energy output of all the alternatives (including the battery) as its also the most work intensive power producer for the player. currently there is indeed only limited use for such a building profile however apart from unlocking gateways - but that would still suffice to give it a right to exist.