I feel like one of the parts of the game that i liked the most was exploring, because it was a good way to find a nice place for a base and to just look at the nice landscape.
I would like more flowers, trees, and bushes. There need to be more biomes, and i would really like some very rare biomes, like a rain forest or jungle, but when you find them they're massive, or possibly kinda small.
I would really like a hidden skill (basically a multiplier) for your stamina, it should start off as worse stamina than you have right now, but if you run a lot it would slowly let you run longer without loosing stamina, or maybe you'd just regain stamina faster.
Generally there is no end goal to the game, so i think i'd be nice if you could make one that isn't like "oh you have to do this," but more like "i want to find this rare bird," or "i needa find this rare biome." This is a sandbox, and I would like very sandboxy end goal options.