If that is the case, then it should be a short-term surge of monster spawns that quickly shrink realms and is over within two or three weeks.
If spawn rates are brought to this level on the long term, then realms will do nothing but fight monsters and will be incapable of going to war against player-controlled realms. The beginning of Dwilight allowed for fun RP while people were establishing the realms' cultures and colonized the land, but there were very few wars.
I'm afraid I can't agree with this, at all.
First of all, "two or three weeks" is an absurdly short time for such a thing to happen. If realms are to be actually shrunk within that time enough to raise the noble-to-controlled-region ratio, the spawn rates will have to be so high that we end up with titanic monster armies smashing everything in their path.
Second of all, if the spawn rates are jacked up, regions are lost, and the spawn rates go right back down, guess what will happen?
Everyone will just take back those regions, thus making it a pointless effort.
It is not possible to have monsters strong enough to significantly shrink realms, and keep them shrunk, without providing the kind of threat that existed in early Dwilight.
But you know what? Even while there were monster threats, most of Dwilight was able to interact with other realms, have wars, and in general lead a mostly normal existence. It was only certain pockets (like Luria) that were cut off from all civilization pretty much until all the land was colonized.