I have no idea if it's been discussed yet, but there's two things I think would be nice to see changed.
First is to increase the rate of the seeds gotten from the greenhouse when harvesting 'plants'. At the rate it is now, you have to go outside into the world to continue getting more seeds in order to plant in your greenhouse. I feel it should, at some level, be sustainable by itself so you don't have to do that anymore. Although, if it's intentionally like this in order to encourage more exploration, then I understand.
Second is to allow players to take water out of the Water Supply module. This is in order for us to be able to take the water and use it in cooking recipes.
Also, I have no idea if this is intentional either, but with the rain collector connected to my water supply, my water supply continuously gains water, even though it hasn't rained since the start of the game. I have never collected from my rain collector. This may be a bug or maybe this is how it works and I don't understand?