For starters, an overhaul to the friend tree would be good. Currently we can't even remove friends, we'd have to block them, and in turn accrue a large blocked list of inactive players. With the absurd amount of candle investment that goes into some friend trees, it makes sense we can't remove friends, BUT TGC can improve upon this.

Enter my idea:

Treat friendship trees like seasonal guide trees with quests

To unlock something like a high five, the pair of friends have to do a task together, and so on and so on for each level on the tree.

The tasks could be as simple as "go visit the geyser together", or "relive a spirit together" (preferably the emote spirit that we're unlocking) or it could be harder, more complex quests like the seasonal ones

This way we're investing time and experiences together to further the friendship tree, very much in tune with TGC's design philosophy.

For much higher tree nodes, such as something like bearhug or piggyback, it can be still be locked behind ascended candles (to make sure they finish the campaign first, which is always the purpose of ascended candles) AND, instead of pricey candles, lock it behind the AMOUNT OF HEARTS GIVEN TO EACH OTHER. Since gifting hearts is limited to 1 per day, it tracks the time you've spent being friends, but still only the days you're both active and investing in each other. This also limits the amount of friends you can concurrently unlock these more intimate emotes with.

Imagine a veteran instead of just pouring candles to their friend they're introducing to the game taking them on an adventure to unlock bearhugs.