It's very difficult to beat a kingdom in a long war when they have 2.15M peasants vs your 700k peasants. It's very hard to control peasants vs a big avian core. In a long war, a huge econ advantage combined with a big land advantage allows taking down larger provinces by bouncing if necessary. BB made this into one of the best top wars in a long time, it's just too bad the age ends before the war could come to it's ultimate conclusion.
Edit: Also, anyone asking for stats can get view on tf.munk.net
http://tf.umunk.net/#war=2&id1=87&id2=368
BeastBlood
31,862,506gc (-38,054,293) 165,741 acres (-27,038)
Emeriti
36,966,025gc (-29,842,767) 206,302 acres (11,204)