So, after reading the annotations and the summaries of some of Brandon's interviews, we have a good idea of what the next Mistborn Trilogy is going to look like.
Here's a summary of what I've gathered so far:
1. The next trilogy will be set either 500 or 1000 years after the end of Mistborn #3
2. Brandon plans to complete two books in the Stormlight Archives universe then write a book based in another universe (maybe a Mistborn Sequel book), then repeat the pattern
3. The main character will burn Necrosil (someone who can cause duralumin effects in others by touching them and burning Necrosil)
4. Sazed will still be god
5. Marsh and TenSoon will still be around
6. Even though at the end of Mistborn #3 there were some teasers that Sazed may try and bring Vin and Elend back, this will not happen
My Thoughts:
1. I really would like to see Vin again in the sequel trilogy. I know it may not make story-wise sense to bring her back, but I really enjoyed her character. I would be satisfied if one of the characters in the new book is a descendant of Vin and Elend, but alas this cannot happen.
2. Hopefully the descendants of some of the other characters show up. I'm sure Breeze, General Demoux (spelling?) and Spook married their sweeties and had children.