When I attach a zipline I think all the grass directly in its path should despawn and not be able to grow back. This would make it so we don't have to build such ridiculously high, FPS-killing towers, to use the ziplines effectively.
I would also like it if the grass wouldn't grow back under player structures. It's extremely annoying having to re-clear the grass from my skybridges. At the very least, you could make it so grass takes a few days to grow back so it's not such a chore.