The Horned Rat expansion is going to be all-encompassing, essentially a whole new game. That means it's time for speculation, educated or otherwise. The most suggestive things for me is that there will be 5 reference sheets, and it seems obvious to me that this is for the sake of remaking how the characters work. I can get that much from Khorne. We can already see that Khorne has a realistic shot at points, but as far as getting dial, he doesn't even need many cards to get his job done. If his dial advancement condition were to remain the same while the cards would change to favor points, Khorne would quickly dominate both parts of the game.
What is Khorne going to want with the expansion? It seems likely that if he's not going to kill figures, he'll still need to kill something: peasants. I have a friend that's already superstitious about his dice rolling being affected by killing peasants, so he's going to flip over that. Of course he'll need cards that work with peasants the way that the Horned Rat works with Skavens. Figure-killing will still be quite relevant, as can be seen with his Chaos and upgrade cards that have been revealed. Skulltaker will add to his domination, and the Bloodletters will give him up to 12 points per round (6 Bloodletter figures). Lambs to the Slaughter seems to be a crap card for him in this scenario, just moving enemy figures from adjacent regions into the region where you play it at a cost of 2 points.
Now, if Khorne's going to focus on points, it makes sense that Nurgle is going to focus on dial. A dial-centric Nurgle will still be balanced, since his is the longest one. If that's going to work though, he can't just be forced into 4 regions. He needs to be able to get dial advancement tokens in a more fluid manner. I don't really know what to suggest with this, except maybe that he has to put one corruption in a region where another player adds corruption in the same phase. This wouldn't really work out with the Horned Rat though, since the Skavens don't actually add corruption. They just work to score ruined regions by their own existence.
I believe Slaanesh will come to enjoy populous regions more. Nurgle will have to abandon populous regions if he doesn't change how he approaches them, and where better for a dark god to make a blood orgy than heavily populated areas? It will still be a relevant area for him. He'll definitely need stuff to help him dominate those regions though, since he has the fewest figures (unless some of those 15 figures will go to Slaanesh, very doubtful). Beyond that, I'm sketchy.
Tzeentch is the biggest question mark. If his dial condition wasn't going to change, there'd only be 4 reference sheets. I'm scared of change coming to Tzeentch, because he's just perfect the way he is. He needs to cause change, not be the victim of it. The Horned Rat's fate will also be linked with Tzeentch. Either everyone gets a new set of stuff, in which case the Horned Rat only gets one total, or else the Horned Rat gets 2 sets of things, leaving Tzeentch completely unchanged. The numbers shown are basically similar to the base game (actually more cards), though there won't be as many Old World cards (no ruination cards at all) to make the room for another Chaos deck.
I also look forward to the new expert cards. Our games almost never go to the Old World's defense, so it'd be nice to have this psuedo-player in the mix.