First suggestion i have would be something like a preferences page to customize what your character finds most relative.
For instance i am a heavy miner, i do not have any skills in the animal kinship or green thumb stuff. all i want to do is mine. So when i am chipping away at my dullite node using the "Enter" key as a short cut and 4 butterflies swarm me, why must i scroll through them all to get back to my node.
Rocks/Metal are always set to lowest priority, even though for me it is my only interest. I think it would be useful to be able to set what your character interacts with.
Each character has different needs so this should span multiple settings, to toggle interactions with trees, animals, people, sign posts and whatever else may come.
My next suggestion relates to how items are used in the game, I keep three grinders on my person presently, and when they are all at about 10% durability it would be nice if i did not have to switch between which comes first in my bag to get each to be used when i select the ore to crush. I do not know a thing about programing but it would be helpful if the "Available use" would act as something that would pool together and grow as you have more and diminish across the board when grinding. this could work for all tools.
As an example say you have 3 Grinders your Grinder pool would be 300/300 and could diminish with use. or two Shiny Picks would be 2000/2000.. etc
My third suggestion which i am sure is in the works, but if it is not, it should be, when i am in a party with a player, the party chat is nice. but it would be excellent if it could show them on the map, i realize i can easily click the players name, get info and view their location on the map, or even just hover my cursor over the name. But if it were possible to make a colored star like the red one for your own player, perhaps blue, and differing colors as you get more players in a party, this would be a nice detail.
Lastly while i am at it, it would be interesting if i could share a home with another player. not going to go further on that one, occurred to me as i was writing this.
I hope these ideas sound good to someone other than myself :) i apologize for my inconsistency with grammar.