Finished a reread of Way of Kings, and looking at the forum/appendices gave me an idea as to the direction of the series. I think that the Heralds of the Almighty will be reformed by the last book. Here are my predictions (in order) for who they will be: Kaladin, Jasnah, Talenel (herald from the epilogue), unnamed art destroyer, Elhokar, Shallan, Dalinar, Navani, Szeth, Rysn (trader that visited Shinovar). As you can see, it alternated between men and women, with five of each. I tried to match the characters as closely as possible to the table of Ten Essences, but had to stretch plausibility a little to make it work. Here are my reasons for my choices, and how strongly I believe I can support them:
1. Kaladin (Sapphire, inhalation, air, protecting/leading): He uses a sapphire to survive the Highstorm, inhales Stormlight for his powers, Syl is a spren associated with Air, he tries to protect everyone and is a natural leader. Solid case.
2. Jasnah (Smokestone, smoke, learned/giving): She uses her smokestone in her "soulcaster" most of all (the obstructing boulder, and the two thieves she wasn't touching), she is very learned, and could be perceived as giving, if you stretch a bit. Fairly solid.
3. Talenel (ruby, soul, fire, brave/obedient): No support for Ruby, his soul was trapped, and then returned, he shows bravery by choosing impossible fights and winning, and obedience by not abandoning the Oathpact. Fairly solid.
4. Art Destroyer (Diamond, eyes, loving/healing): eyes look at art? not much here, needed a woman for the slot. Weak.
5. Elhokar (Emerald, Just/Confident): Wins an emerald gemheart in the hunt, isn't very just or confidant now, but could easily become so later. Fairly weak case. Adolin could also fit here fairly well.
6. Shallan (Garnet, Blood, Creative/Honest): Uses a garnet to reach Shadesmar, soulcasts the goblet to blood, bleeds lots when she "attempts suicide" backbreaker powder is a blood poison. Symbolheads could be associated with blood (see ch 4. epigraph, "I'm dying, aren't I? Healer, why do you take my blood? who is that beside you, with his head of lines? I can see a distant sun, dark and cold, shining in a black sky.") She is extremely creative, and genuine. Solid case.
7. Dalinar (Zircon, Oil, wise/careful): Dalinar needed to be in here somewhere, and he fits best with wise/careful by the end of the book. Fairly weak case.
8. Navani (Amethyst, metal, resolute/builder): nothing with Amethyst, metal is needed to build fabrials, which she does. She also is very determined, not too sure about "builder" though. Medium strength case.
9. Szeth (Topaz, bone, rock. dependable/resourceful): Windrunners were described as blue and yellow (IIRC), Kaladin is Sapphire, so that leaves Topaz for Szeth. nothing for bone, but rock could easily be his oathstone. He is very dependable and resourceful, succeeding in all of the tasks given to him. Strong case.
10. Rysn (Heliodor, pious/guiding): A heliodor powered the sensing fabrial that she set up. Not much here either. Weak case.
Some things that I know I missed: who are the pictures in the chapter headings of in each of their viewpoint chapters? as well, I seem to recall hearing that all of the main characters were introduced already, but I'm not sure when.