Not using their resources as sufficient as Aurvandil.
Fair point. On the other hand, Aurvandil's running a military either at the limit or beyond what they can properly afford. I'd expect there's less strain on Madina for the same output, or close enough. Course, that's all well and good if Madina can raise their game but if Aurvandil's smaller size allows them run higher tax rates and recruit for cheaper, then perhaps Madina won't be able to sufficiently raise their game to beat the fortifications.
Which, obviously, is what players in both Aurvandil and Madina are pointing to. One side or the other need to mess up to actually stand a chance. If it wasn't for Nathan stating that Madina could run out of gold soon, I'd have actually suspected Madina would be able to afford to quietly build a warchest to invoke for a quick and decisive strike. If Aurvandil is making proper use of Evanburg though, perhaps Madina don't have that luxury.
Who's to say? Well, maybe the people in the realms in question. From my perspective, its all good though. No one like's sitting in a city doing nothing all day, every day. What will probably decide this war is the bleeding of nobles who are beginning to get bored senseless. That's no theory, since Barca's already received at least a couple for that precise reason.
We'll see, I suppose.