Now that Natlan quest has finished I guess I can say my opinion on the region overall.
It's the worst region in the whole of the game/Teyvat.
Map - we were promised a dark and dull map where wars constantly rage. Instead we've got some fan service, colourful and "cute cute" map design. Not a war torn land, but a paradise.
I give it 1/10
Lore/story quest - Now this is a tough one. Il Capitano is the best character in this archon quest, well designed and thought through.
Everything else... sucks. Again my opinion, is that everything in the quest has been too sugarcoated and marmelade. All characters look as if they were designed for a little kid to spend more money on wishes, not to fit the lore of the world.
Note: Mavuika is awful in every aspect from lore to the design. P.S. A motorcycle?!
I would give the archon quest a 4/10 due to Il Capitano. 2/10 if without him.
Overall absolutley nothing makes me like the region or the lore of the region.
I had a similar problem with Sumeru map/region design and architecture, but at least Sumeru had THE best/most interesting Archon Quest in the game.
Natlan is the region I will not remember and to be honest, the region I would like to forget.
My last hope is Snezhnaya. If that will be Natlan-like, I guess I have wasted 4+ years of my life playing this game then.
