Whether it be meta tools or apps, or literal concepts like a mineral or a race, for example, a must for me is for the world to be built in a believable manner, and at the most simple, following some decent climate rules without much restraint.
my favourite would be drip plume ice worlds with hotspots that allow for rainforests in 80 Celsius steam zones, very exotic, the temperature regulated by these hotspots.
I rambled on too much…
I build for ttrpgs (GURPS in particular) and like to run many campaigns in one world, so having some believable inter-nation politics / conflict is a must.
Also, if there are gods or super powerful beings, even high level spell casters there needs to be a good solid reason why they aren’t the ones who are saving the world. The Forgotten Realms made me question that too much, as a player I was meeting all these high level beings and they told me to go into the pit of evil bad guys who are going to take over the world.
I generally solve this problem by presenting gods more like they are in IRL religions, inscrutable and unknowable. This also allows for things like crises of faith, which would be hard to pull off when you have tangible evidence of your deity lying around. As for why they’re so aloof, this is my go-to explanation.
I like it, as long as there is a why (and it does not even have to be obvious, it can be discovered as the story progresses). I like your solution, I’m always a sucker for giant cosmic space god heads.
I based the idea on Unicron from G1 Transformers. For the longest time I called the structure in my conworld Yinrihcron in want of a better name. Now the name is used in-universe by humans.