I must admit, having spent the time to recruit each city to my aid, severe disappointment was coped with when I reached the battlefield. Though, remember Oblivion was the pinnacle of next gen games when it came out, so if they made the battle huge most computers would explode, killing thousands.
It was cutting edge, all the TES games have been when they arrived
My PC handled Oblivion just fine until it decided to start to crash for some reason, I am now playing it on the PS3 and on a 52 inch screen, while not running as smoothly as on the PC it sure looks pretty