RShara

The Stormfather said that it was due to the genuine fear that the KR would destroy Roshar, as they did Ashyn. That plus their god basically promising them that they would destroy the planet, and they probably thought they were doing it for the greater good. As for killing their spren, here's my "The spren were in on it" theory:

It seems to be just what Wandering Investor said--her ability to create illusions just makes it easy to lie to herself. Lightweaving is just Illumination.

Nope, we haven't yet. It's a tough one!

We've only seen two types of Squires so far that have spent any significant amount of time with their powers (So not counting Vathah, who we see able to Lightweave badly for about 2 minutes). Windrunners, who do get both surges, and Skybreakers. Novice Skybreakers neither have spren nor are accepted as a Squire when they "swear" the first Ideal, which is why they can't access any surges. A "natural" Skybreaker with a spren should be able to access the surge before even swearing the First Ideal. Once they are accepted as a Squire, they are then able to take advantage of surges. It's not the Ideal but the fact that a full Skybreaker is willing to accept them that grants them the surges. This is literally an example of what I mean by Skybreakers being heavily structured. There was only a passage of maybe a week or two between Szeth swearing the Second Ideal and the Third Ideal, so I don't know if it would have been enough time to fully bond the spren before swearing the Third Ideal.

Good point. Also, we get a couple of Gaz PoVs, and there's no hint in them that he's not what he seems.

Lift used both Progression and Abrasion before the second Ideal. She used Growth to make seeds grow to open the window in Azir, and Wyndle said she could use Regrowth with practice and food. Shallan was able to soulcast and lightweave, she soulcast the goblet right when she said the Second. Dalinar swore the first two Ideals together, so it's impossible to say. I was referring to the Third Ideal, not the Second, above, but the point stands either way. Kaladin didn't even realize he could fly and such until he saw Szeth do it. I think it's more a matter of perception and experimentation than a hard limit. Yes, I agree that the further you progress, the more control and ability you have with the surges. But I don't think there's a limitation on when you can start using them. Also, remember that Szeth was actually a Skybreaker Squire up until he swore the Third Ideal. There's no hint that the Squires can't use both surges.

Are you thinking they are the same person? Warbreaker takes place some time before WoR...possibly as much as 300 years, so they're not likely to be the same person.

Sorry, I felt it was clear. The constellations were thought of by the person who commissioned the piece, and they are a picture of the night sky from a specific location in the Physical Realm. There aren't stars in the Cognitive Realm. One person's belief (or even a group) wouldn't be enough to change the shape of the CR, I think. All planets are technically closer together in the CR, because space that people aren't thinking about or living on is compressed. There's only a small amount of interstellar space between planets in the Cognitive Realm. People know their planets are round in the cosmere. It's mentioned several times. However, when you look around yourself, you don't think, "Look at how round the planet is today!" You think, "My those plains are flat." This is what I think causes the CR to be flat. While you know that the planet is round, you perceive it as flat on a constant basis. For Nightblood I just used those three as examples, since you had a lot of questions, theories and observations, and a number of them were answered by Brandon already. I'm not up to pasting every single relevant one into this thread, so my suggestion is to take each question and try a number of search terms for it, and there's a decent chance you'll find an answer.

And I still think it's because of the heavily regimented way that Skybreakers advance and use their powers. Technically he could use it at any time, but because of policy and rules, he wasn't allowed to use it. It doesn't make sense any other way, since Shallan, Kaladin, Lift, and Dalinar have all been able to use both surges right away.

Nah. Trell had a brother, Nalt, that they didn't like. And they thought Nalt was ostentatious because of the glaring bright eye, whereas Trell was better with his thousand tiny lights. The Purelakers liked sunlight but I don't think they thought that Nu Ralik was of the sun, or that Vun Makak was the night or stars.

Browsing over your questions, a good chunk of them are answered or addressed in Arcanum, wob.coppermind.net. Have you taken a look there? For example:

Unknown, but I feel like it would be more complicated than trapping a spren in a gem and carrying it off.

My guess is that Bavadin wanted her people on a planet that was very difficult to get to or even find. We know she also locked the planet down for something like a thousand years, so that even Cognitive Realm travel was impossible.

Right, the debate is whether the Shardplate is an illusion or was really there, and whether Radiant was wearing it when Jasnah came up. He doesn't say that they only get access to Division after the Third Oath. He says they will be taught how to use Division after their Third Oath. I'm pretty sure they can already use Division, they just aren't trained in it because it's more dangerous; the Skybreakers are very rigid and require strict obedience.

Aimians aren't human at all. Siah Aimians with the blueish skin can obviously change their anatomy to a degree. They've bred with the Natanan people, and that's why the Natanan have blueish skin. Dysian Aimians aren't really even humanoid. All the Radiant spren we've seen are humanoid in their full form. Horneaters and Herdazians both have Parshendi blood, which is where the crystal fingernails and extrahard toothparts are from. Also, Brandon has implied that Aimians were created, similarly to humans and Parshendi, and that's why they can interbreed. Light eyes are definitely a remnant of Radiant or Shardbearer heritage. There's a part of the sDNA that gets changed when someone wields a Shardblade or is a Radiant, that causes their eyes to turn the same color as their Order's gemstone (or the Order that the Blade used to belong to). For the other weird genetic quirks, my personal theory is that Rosharans have a tiny bit of Returned blood in them, which has caused certain physical characteristics to become locked in their genes.

lol

They aren't yes or no questions! Taldain is in an unstable orbit, but it only needs to last a few thousand years. And Bavadin is likely helping to keep it in place. Its moon, at least, is in an impossible orbit without magic. The tree symbology, we don't really know anything about. It just has some significance to the Shard, and seems to be related to its isolationism.

But the basis of the argument is that Radiant is the one that was Shallan at the time, and Radiant wore Shardplate. Iirc, Radiant looks almost exactly like Shallan, only the hair is coifed and she's wearing armor. So if Radiant wasn't wearing Shardplate at the time, that sort of collapses the whole thing, doesn't it?

Crackpot theory: It was Hoid playing his flute to lure Syl to Kaladin.

I think it was illusion, because I feel like Jasnah would have said something if it had been real. Jasnah made a point of asking Shallan if she even had her Plate yet earlier. So seeing her accomplish this should have provoked a response.

Well she carved it into a tabletop too. It doesn't seem like it's a particularly secret symbol.