Just why is it so inconcievable that the Imperium would be stronger in the Marches than in Foreven and the Zhodani would be stronger in Foreven than in the Marches?
Hans,
Because the Imperium is closer to that portion of Foreven in which Imperialline's ill-concieved Avalar polity is said to exist than the Zhodani Consulate? And because your perception of the border between the Consulate and Imperium being limited to the Jewells is too narrow in a both political and astrographical sense?
Just as the de facto border between the Imperium and Heirate is a demilitarized region nearly a sector in size, the de facto border between the Imperium and Zhodani is a region running from the Jewells spinward and rimward through the Marches and on into Foreven. Those Foreven subsectors spinward of the Five Sisters are part of the Imperium's de facto border region with the Zhodani and the Imperium will be just as busy in them as the Zhodani are in the subsectors over their own de facto border region beyond their de jure borders.
After their victory in the Fifth Frontier War, the Imperium took steps to lessen Zhodani influence within the border region between the two powers. They reordered the government of one Zhodani minor ally, the Arden Federation, and essentially destroyed another Zhodani minor ally through partition, the Sword Worlds Confederation. Suggesting that they'd then ignore another Zhodani ally in the same border region, the alleged Avalar Consulate, is quite frankly implausible. When you remember that the alleged Avalar Consulate is even larger and thus potentially more dangerous to Imperial interests in the border region, suggesting that the Imperium wouldn't take steps against it or its political alignment is even more implausible.
SMC and JTAS' TNS reports tell us about the various measure the victorious Imperium took to lessen Zhodani influence in the border region the two powers share. The Avalar Consulate isn't mentioned, not because the Imperium didn't take steps against it or because those steps were somehow omitted in canonical reports, but because the Avalar Consulate didn't exist then and has never existed.
Like IRIS, the Avalar Consulate is an ill-concieved addition to the game created by well meaning Hobbyists and inserted into canon through irregular means. Like IRIS, the Avalar Consulate should be retconned out of existence as soon as practical.
Regards,
Bill