A farming system would give a purpose to many different blocks, and would make space stations more interesting now that we'd need a stable supply for all our faction members/NPC crew.
In the link above there are suggestions for alien life. Also here:
http://starmadedock.net/threads/big...es-and-unidentified-entities.6341/#post-90965 Cultivating alien species as an expansion to astronaut mode would need some sort of food mechanic, and stringing together DNA chains to create our own species could benefit from additional protien/carbon chains.
I played a game called Starbound that has farming/hunger that only gives a buff (you can't starve to death) - this made the entire farming system almost pointless. My quickbar and inventory space and time was better allocated to more meaningful items.
We don't have to worry about surplus crops like in Minecraft because Starmade shops and trade systems are much better. I freaking hate Minecraft village trading. In Starmade, farming crops = trade good = money = ore = shield. This seems much more realistic that spending FP to respawn asteroids once a System has been mined dry.
I'd also suggest putting in a crop-health mechanice. As in real life, if you keep growing the same crops in the same soil year after year you get soil depletion and are more likely to develop diseases - meaning that future crops are more likely to fail without some sort of intervention. I might have a super-productive 100x100 farm, but if the rate of disease is 1% then that crop will have roughly 100 sick plants which could easily kill the whole patch.
A hunger system would provide an alternative battle-mechanic during faction wars. If you can blow up the farm and shoot down supply runners then the players will start to starve to death (or starve into debuffs at least). Or we could bring out diseased plants into their crops.