I think it's actually more of a brand problem than a geography problem.
Ohnar came about after Lasanar collapsed, which happened in a messy and unplanned way under Prime Minister Vulpes. Ohnar and Ohnar West were both sort of cobbled-together realms because the Dukes needed something to belong to. Even when Galiard was Ohnar West's PM when it was larger, I never had any notion of what it 'meant' as a realm except that it provided a convenient umbrella for largely autonomous Dukes. Toupellon had the same problem.
The one thing that Lasanar did really well during its prime was that it established a very firm feudal structure to support its Republic government. They had this idea of the ruling body (the Grand Council) as a collective sovereign, and even though Dukes had a lot of pull, they were made to swear fealty to the council and publicly support whatever it decided. There were semi-regular attempts to weaken the grand council, usually by Dukes of Colasan, but they were all executed or killed in battle. After that happened two or three times, everyone figured out that maybe the grand council wasn't such a bad idea.
Even before it had a bunch of guys from Arcachon, Ohnar was at best a non-functional realm: it never made a material difference in a war, it never colonized anything, and it never aspired to (much less achieved) any kind of greatness. As much fun as I make of Sartania's annual blow-ups, they always happen in pursuit of something awesome, even if it's also ridiculous. Ohnar was always just ... meh.