#1 - Could there be a way to highlight hostile creatures so you can tell they are going to be hostile before you get close to them? Perhaps they could have a red outline or something. It gets really weird when you're digging and you run into a creature and have to assume it's gonna jump all over you. I know it makes a noise, but only when you get into range. Maybe even if it was an item that highlighted them for a short period - on a reusable cooldown. #2 - I am fine with poisonous waters underground, but can we not have those 1 block poison spots that you can barely see and poison you when you walk over them? They bug the heck out of me!
I like these features! They make the game more challenging, and makes it require more skill to adventure!
Part of exploring new planets and systems is learning about the indigenous species that inhabit them. All it takes is one encounter with any mob on a planet to know if they are hostile or not, and ya, those one block bits of poison and lava can be annoying, but I think it's just part of the danger of mining an unknown planet, interstellar mining is a hazardous occupation.