As per 2e (because 3e hasn't really gone into detail yet), Heaven is intimately involved in the maintenance of Creation, but not it's *governance*, outside of corruption or agendas. So the Bureau of Seasons does influence the weather- that's it's job. But the BoS is also one of the exceptions of Not being corrupt (for the most part), so it is more interested in Doing It's Job than ladder-climbing and following the rest of the 'Heavenly Bureaucracy'.
Like- if you actually look at the Celestail Bureaucracy from chinese mythology, it's a very simple conceit and indictment of mortal goverments of the era: The world doesn't make sense, full of things doing busywork beyond the insight of the peasant masses- just like the high-minded scholarly and official castes in those periods. To explain how the world worked in apparently arbitrary manners, the original Celestial Bureaucracy is full of corrupt, inept or otherwise disinterested beings who are not doing things the way a human can understand them.
Just like how mortal goverments do things their constituents can't understand, or think aren't productive.
In practice, Heaven has exactly as much involvement as a given game/story dictates- that's the point. It's meant to exist on a sliding scale of 'can fuck with your PCs' and 'will not fuck with your PCs'.
This is also fundamentally why over-characterizing the incarnae is a narrative mistake, because it makes the game and stories less about the Exalted (and less about the PCs) and more about this somewhat static, almost formal 'program' of a setting.
To build on what Chung was saying earlier- you don't want any 'Higher being' to be the goal of a story to 'fix the world'. I mean yes it can be done for Your Game, more power to you, but the actual base setting needs to be written with an eye towards enabling and empowering the players over the actors in the setting. This is as much a question of internal consistency and suspsension of disbelief as good game-writing.
Like, across my time playing Exalted, I have had to consistently teach players that invoking the Unconquered Sun is not meant to be a thing that is done- that his input is fallible and/or biased. That while he has vast powers, and can do things- the things he chooses to do are not comprehensive. It's the difference between 'The Sun blesses the creation of this empire' and 'The Sun marches out of Heaven at the head of his war host to conquer the Realm at your request'.
Players of Exalted... there's a conveyance problem, of really getting deep into the kind of game Chambers and Grabowksi were trying to make way back in 1e. Not to say they're absolute authorities on how to play the game either. These distant, aloof, uncaring or outright manipulative gods are either allies of conveience, or are actively trying to get theirs as much as you are trying to get yours. Not to say they're jerks- that's a problem that 2e actually went out of its' way to write a sidebar for in RoGD1- the point is that Creation as per 1e and 2e was written with a cynical eye, but not a cynical obligation.
Like, if you tell me that I have to play the Exaltation as this hunter-killer seeker system designed to uplift a patsy race into credible weapon platforms to fight god-forging titans, I'm going to dislike the imposition. I enjoy and agree with that interpretation of Exaltation itself, and I like being able to take advantage of it. Like... as a storyteller, I like the option of being able to take a player who views Exaltation as this Glorious Chosen of the Gods Divine Right of I am Awesome, and then explain to them in-setting that no, you're not special beyond qualifying- you're lucky, and then what matters is all on you. The followup though, more importantly, is then putting the agency back in the player's hands saying 'You now have all this power, and YOU have to be the moral authority. You can't offload it now onto this distant god who is only nominally affiliated with your powers."
Fundamentally, the goal is to provide a bigger toolbox- I dislike 3e's approach to an 'unwritten' toolbox, where things are vague or indistinct for the sake of open-endedness. I however see that as blank canvas syndrome and a drought of precedent to build off of- sure, 2e had too much boilerplate attached to explaining Everything, but those explanations helped me run better games.
So casting the Sun as this 'endgame' solution to Creation's problems is in a way just as bad as the Reclaimation plot, Abyssal reincarnation and Devil Tigers- they're paths but are in fact the only path that matters. The Sun cannot be the solution to all the setting's problems. I however am firmly of the mind that the Sun should be something a storyteller is equipped to use to enrich their games. This applies to everything- if the detail isn't included with the intention of improving a player/storyteller experience, it needs to be evaluated very careful as to why it's being written about.
A good example of this done badly is the Daystar itself- the actual flying airship. I know 3e is walking back on it, but that's not the point- the point is that it's an example of how Not to do it: The Daystar's problem is that it is all tell- there is no organic way for a player to encounter it unless the storyteller tells them, or the player is allowed to, out of character, recognize it's existence. Oh there are ways to justify it- past lives, visions from gods, any number of ways to convey the information-
but the Daystar itself and it's associated 'plot hooks' are all contingent on the notion that you will somehow come to know of the Daystar itself. A much better 'similar' thing was done wtih the Five Metal Shrike, in which there were enough hooks seeded in the setting itself that you could investigate it and in turn determine how to take it over for yourself. The Daystar, by contrast, was only something that NPCs or 'made up' hooks could engage with. Granted the FMS was one of those 'Solar Only' plothooks, but I'll be perfectly blunt- the game was largely in part about the Solars returning as primary actors. That's reasonable- I agree that other splats did not get the love they deserved though.