>Something Boreal
Maybe. I might add a couple of additional sources. But I think you underestimate the amount of glacial water that becomes available in the late game, which is when you actually need it the most. And if you have no idea what I mean: look at the entrances to mines.
>Could you just have the higher tier versions of the gloves/boots stack the previous effects onto the upgrade?
I saw several people actively considering their equipment during their playthroughs, and I don't want to remove that from the game. Verdant sandals may need a buff, though.
>Is there a win condition in the current game?
No. If you see no active quests (besides Ricardo's friends, which is always active), it means there is nothing else left in the story. All that's left is to explore until you've had enough.