Those figures are quite interesting. It looks like Astrum and Swordfell have stayed roughly the same, like Luria, Fissoa and D'hara have seen increases, like Asylon, Barca and Morek have seen big drops and obviously Niselur and Corsanctum no longer exist.
So what I see there is basically the western realms losing a large number of nobles, including the surviving ones, which is to be expected with realms which have lost their homelands, but this in turn has driven an increase in nobles for the eastern realms with the exception of Morek which is managing to buck the trend by shedding nobles rapidly - almost certainly due to reasons unique to the atmosphere in that realm.
Which means that overall the closing of western Dwilight has been a partial success and a partial failure. On the one hand, it has driven an increase in noble density in the south (I suspect the north would have seen this decline pretty much no matter what happened) but it has also lead to a large fall in total noble numbers as well - which is not surprising considering how demoralising this must have been for nobles in the realms hit by monsters.
It'd be interesting to see what the numbers are like for other continents. I get the impression from the limited perspective of my characters that it's worked far better on EC than FEI and I have no idea what's happened in AT.
D'Hara's "growth" (in quotation marks, because it only increased in the first block, then remained constant for all of the rest) seemed pretty much sustained by new characters being created while older characters phase out. I did not witness any significant immigration there, if any immigration at all.
Also, as for the appeal of knights and new regions, I'd say it varies on the realms' geography. A city-wealthy realm that expands is likely to lose raw income, because if a knight moves from a city estate and moves to a rural lordship, the total output, efficiency considered, is very likely to be less gold. On the other hand, many people are likely to prefer a lordship even if their income drops a little for it, and more regions does mean for capacity for infrastructure (such as RCs and thus recruitment capacity), increased food security and a few other perks.
