Dravs

Honestly when I read this quote I get the feeling that Brandon was watching Stargate when he thought of the idea for Shardpools. I know he likes to keep his magic systems enshrined in science so is it possible that the Shardpools connect to each other literally via wormholes? With Shadesmar being another method of travel between the stars (if you know how)? Possibly you need to know the location that you are travelling to, to "dial" the location, as most of the Cosmere science/magic is made with intent as an underlying factor? It could make a bit of sense as to why Hoid could not just travel to the Well of Ascension in Mistborn from a different Shardpool, as he did not know where it was to travel to it. He was likely stuck on Scadrial for a while, as i suspect he was the person who created the Terris Worldbringers religion which he also seems to have started on Roshar with the Worldsingers.

Abrasion and Friction probably means they can set the air on fire, which is pretty baller I would say.

Wasn't there a WoB where it was stated that hemalurgy works on all shard worlds? Is it possible that the Heralds are hemalurgic constructs and Taln is being controlled in the same way Marsh was? Or possibly the real Taln was hemalurgy spiked and the person who received it now has the memories (albeit scattered and jumbled) of Taln?

This theory makes the most sense to me at the moment, as Talns blade would have been the only one they wouldn't have had access to, and therefore his oathgate would have been the only one that they could not lock. The heralds seem to have access to fabrials that no one else does, so it would make sense that they would be more knowledgeable regarding their construction and control. Now that they have Jezeriahs honourblade and his seat presumably being in Alethka, and with Kaladin going there in the next book, it would make sense that after the Everstorm transforms the parshendi Kaladin fights in a retreat to get everyone into the Palace as it is defensible, and at the last moment they work out how to activate the oathgate using the honourblade there and get everyone through. That feels like a very Brandon thing to do. Would make a great avalanche at the end of the next book. As to why they were originally locked, I imagine the Shin either had a hand in it, or at least know the reasoning. Urithiru is holy to them for some reason, and they have all of the existing honourblades. Possibly they saw the betrayal of the radiants coming and locked them out? They would have a means and motive to do it.

This is kind of what I figured, that the gemhearts grow like a pearl would in a clam, except in this case they grow from infusing stormlight, and the stormlight in turn infuses the animal when it pupates and causes it to grow. I think this is Roshars form of animal evolution. I reckon at some point in the series they will find where the chasm fiends originate from and just find fields of Chull who have been allowed to pupate over and over until they evolve.