I want an item system more reminiscent of a classic Zelda game. One of my least favorite aspects (among many) of BotW was the fact that you obtained nearly all of your unique items and abilities in the tutorial of the game. Everything else was just some boring dime-a-dozen weapon that you only got because “its number is higher than the one on my current weapon” or the champions abilities at the end of each dungeon that felt like complete afterthoughts and nothing more. Link feels completely static as a character in his versatility because his toolset is already as good as it will ever be within an hour of playing. Putting a rune in each dungeon alone would have made the game immensely more enjoyable IMO, even if you didn’t change anything else about said dungeons.
In the same vein, I want more unique abilities, and a lot of them. You don’t have to reinvent the wheel here, give me some classic Zelda items in addition to whatever new stuff you’ve got planned. I want to be able to walk into a cave, find a completely unique item, and have said item permanently be in my Inventory for the rest of the game as a tool that I can use to complete a task as necessary. Exploration in BotW felt completely pointless because almost nothing you found ever made you permanently more capable than before.