I am looking for two hopefully simple lightweight mods that affect the basic mechanics of the game:
Sturdy Saplings: Saplings no longer uproot and pop out of the ground if they are in a low light level and do not have an unobstructed view of the sky.
This would allow players to make automated underground tree farms without having to put tons of light sources in it taking up space that could be more trees, just to prevent the trees from blocking the surrounding lights.
Less-Irritating Lava: Lava now dries up when not flowing from a source block, like water does.
Currently lava will leave partially dried up puddles where it has flowed even after all source blocks have been removed. This makes cleaning lava a huge chore, especially in large automated mining facilities. Ideally lava would still have the flowing speed and distance as currently, just dry up when the source block that caused the lava-flow is removed.
Small mods like this that don't add a lot of blocks or other mechanics allow players to customize their game experience easily to fit their playstyle, without possibly causing conflicts in other mods. I hope someone takes the time to create these mods.