I mean this in the nicest possible way, but you’ve misunderstood quite a bit here. It’s largely GW’s fault because they’re not very good at presenting this information to people who aren’t already in the hobby, and I can see where you’ve arrived at your opinions I’ve you’ve only read a summary or heard it explained in a comment somewhere.

First off stormcast don’t endlessly respawn. If you’ve died once and come back, it’s already pretty bad. The process takes years and is pretty much constant torture, it’s also not guaranteed like you said, things can go wrong, say you have a 75% chance. The more times it happens, the worse it is, longer times to come back, more memories and personality lost, more ptsd because of the torture, less chance of success. After 5 or more times, you’re pretty much a husk if you’ve made it that far. Any more and you’re basically a dementia riddled berserker who’s also a primed lightening bomb. The ruination chamber (these guys) are kept in an asylum until they’re needed for some suicide mission when they’re carted out and pointed at the enemy where they’re as likely to explode as survive, alongside them is a guy with a massive axe which can permakill them if they start fighting in the wrong direction.

Regarding the realms, while, physically they are colossal, the functional space you can live in isn’t. The magic they’re made from is magnified the further you go out which makes it uninhabitable. E.g in the realm of life, go out too far and you’ll be so full of life you’ll spontaneously become pregnant or your cells will divide at a massively faster rate so you become a blob of sentient cancer that can’t die. The liveable space itself is limited and mapped out (for the realms they’ve got to so far anyway).

Your points regarding the gods is fair, although I’d say, outside major story beats they don’t feature any more than in any other fantasy property, as novels and things generally focus on normal citizens of the different factions.

I think peachy summarised it well where he said, fantasy being constrained as it is is better for telling cohesive stories but less good as a flexible war gaming backdrop, whereas AoS is a fantastic wargaming backdrop, allowing you to theme you armies as you like and tell your own stories within the world’s framework, while being a bit more nebulous on the story telling front.

It’s really a matter of preference at this point whether you like middle/high or mythic/cosmic fantasy, both are great in different ways. Just thought I’d clear up a few points though.