Would be nice if the Grappling hook and Pickaxe were both one handed so we could actually hook somewhere and mine at the same time. Also Adding weapon sets up on the toolbar would be awesome as well, lets say you'd have a set of two one handed weapons and a set of one handed guns or any other combination of weaponry you'd like to use, and for example if you press keys F1,F2,F3 you could switch through the sets you have created. So lets say you are fighting a melee monster and suddenly a flying one spawns you'd be able to quickly switch to your ranged set to deal with that enemy. This would be really nice with shields as well, switching from an double pistols to a shield and a sword.
Pick axes should require two hands to use, it makes sense to get the strength someone would need to break stone. Unless space stone, or whatever you are digging through, is weakened by the suspension of disbelief. The grapnel I can see only needing one. Since it is made up it doesn't really matter how many hands it takes.
Also i think there should be a planet log in the the travel panel of planets that have been visited so you know you wont be going back to a planet you've traveled before or maybe you want to go back to one to explore some more!
I like that last thought. I think it would also help people find their way back to places they also visited. Maybe have something like a captains log. You could even put in notable events but that is just a casual thought...
I don't see much use to the grappling hook as it is right now. Although good for swinging around and getting around, not much for anything else. What I wouldn't mind is it just keeping the grapple like that, but add an upgrade to it that uses the grapple in the recipe to change it into something like 2 of the people mentioned above; Belt or wrist item. From there it might be used with a button... As to the second thing mentioned, that has been a common thing suggested. Seems like there are so many variants to that idea, log being one of them, a console version, and even part of the star map selection. I would love something like this, especially if what namable within the log and could add a small personal description.