I don't know if I'll ever get to siege weapons, so cutting out spies will quite likely prevent me from having a chance of victory. I'm okay with that though if I get a crack at some decent Mongol stacks.

BC's Mongol wars are some of the most fun I've had with MTWII. Their generals, even in 1.05, can 'swim' through thousands of cheap spearmen, and don't even think of bringing javelins against them. It makes for some great fun!