You erroneously believe that a new realm in Paisly could somehow do something to prevent northern realms from sailing to your lands.
There's nothing that anyone in Paisly can do to prevent northern troops from sailing south, and sailing would be the most logical path for any non-moot realm to attack you. There's no such thing as a neutral zone. A buffer state between yourselves and Terran, sure, but no more.
Well, this was all decided before sea travel was implemented, which now gives realms a ridiculous fast means of attacking anywhere without being located before hand. The Paisly realm would still be a land barrier to Terran and D'Hara, and to a lesser extent a threat to Barca not that it's needed.
Plus, I.C. Mendicant still has complete faith in his Marine Impériale that we roleplayed, though no such counter balance exists in actual gameplay terms.
But as for a neutral zone, well the Paisly realm will be pretty neutral, or at least Aurvandil won't allow them to overly favour us. The Paisly realm will set up a new dynamic of politics in the south, which is the intent. Aurvandil won't be able to march north without violating the borders of the realm and thus declaring war, and the same for Terran.
