Ok, so it would be a pretty good guess that the next book for this game will be Nurgle, so I am going to throw out my predictions.
First off, Archetypes. There will likely be four, two human, two CSM.
CSMs- Plague Marines, Obviously, and I am guessing Warp Smiths, not specifically Iron Warriors.
Humans-
That is a bit more of a toughy. I could see some type of corrupted Magos Biologis dealing with the spread of plague. No idea for the other.
Any thoughts on what this book will add besides the general theme of plague/decay?
Also, title. I am going with Tome of Decay as my first guess. Tome of Plague as the second.
Thoughts?