To add to this train of thought:
- the recent black library contest had 3 allowable settings: vigilus, Comorragh and Armageddon. The latter's crusade supplement has been teased, imo too early to be sole focus of the end of edition campaign. The other two could very well be up for grabs
- There's a lot of rumours around a Corsair boxset, who could more readily feature in a comorragh storyline than the other two
- there were a few murmurings about prophecies of the Khagan (foilrak and such)
- the last few editions had the last faction to get a codex feature heavily in the end of campaign storyline