Going back to the issue of who is depicted in Shallan's sketch, I wouldn't be so quick to dismiss Isomere's suggestion that it's the king of Jah Keved whom Szeth assassinates. I had previously concluded, as most people in this thread seem to have, that the scene Shallan draws is depicting her father's death, but my friend is reading WoK for the first time and he mentioned the sketch to me and my mind jumped immediately to Szeth and the king before I thought about Shallan's father. Then he mentioned that in the next Shallan chapter she hears a voice (presumably the cryptics) ask her:
These are also the king's last words, directed at Szeth, before being killed, which adds another link to that scene. It's worth noting, though, that the cryptics ask Shallan this again in Chapter 45 right before she soulcasts the goblet, so it is entirely possible that this is unconnected to the assassination. It does seem like something of a coincidence though that Shallan mysteriously draws a dead brightlord in a dining hall and then next chapter she just so happens to hear the dying words of a king assassinated in a dining hall...and I've come not to trust seemingly innocuous coincidences in Brandon's work to actually be coincidences.
Shallan's sketch is described as follows:
While it's possible that this is describing Shallan's father and her home, I find that's a strangely aloof description if it is. I would think there would be some element of recognition that the room is from where she grew up or that the corpse is her father. I know Brandon had Kelsier hold back important info in his POV's but I've heard Brandon say multiple times on Writing Excuses that he felt this was cheating and he only did it because it was essential to the story, and even still he still would generally at least signal that Kelsier had a secret he was refusing to think about. He does this elsewhere with Shallan, but I don't see it here which seems odd if this is a depiction of her father's murder, particular because hiding that the scene was about her father's murder is hardly essential to the story.
It does sound to me, though, like it could be describing the scene where Szeth kills the king. He interrupts a feast, so there would be a half eaten meal on a long table, and the description of the swords on the wall reminds me of a great hall in a castle where a feast like that would take place. This could also explain the blood (I had always assumed Shallan killed her father with her shardblade, so the blood seems weird to me if it is her father. I don't remember the quote that made me think this though). Szeth slams into the king and breaks his arm before finishing him with the shard blade. If that was a compound fracture his arm could have bled heavily before he died.
I do agree that there is no way that Shallan could have witnessed the assassination actually take place. In fact I doubt it's happened yet. IIRC, with the exception of Elantris and WoT, Brandon has said his books are strictly chronological, and the assassination comes after the sketch and her hearing the voice.
This is precisely what I find so interesting about this possibility though. We know some degree of future-sight is possible in the Cosmere because Hoid does this (admittedly with feruchemy, but its possiible the same affected could be achieved with different magic systems and this is proof that future-sight doesn't violate the laws of the Cosmere). I can only wonder if Shallan's connection to the cryptics is making her manifest some sort of prophetic capability. I admittedly don't know as much as I probably should about how the magic systems on Roshar work, but presuming Shallan is a lightweaver and her surges are illumination and transformation I don't know that predictive ability would fit into either of these...perhaps illumination if taken figuratively, but I would be inclined to take it in the literal, light manipulation sense. If this is actually a picture of the assasination, then, it could have interesting implications for how the magic system works on Roshar because it would suggest you can manifest abilities though a spren bond beyond those covered in the surges.
I'm still far from certain that the sketch is actually of the dead king (Shallan's father or some other random dude are definitely possibilities), but I think there is at least enough evidence to make this worth considering, if only because its implications would be really cool.