Yes, it's harder to blitz... at the beginning, as a Catholic.

However, I have a remedy for that. Spammed small clusters of cavalry/generals.

You lay seige and wait for them to sally, and then you destroy what's inside. Reduced seige times, highly experienced troops, low upkeep, and a fast expanding territory. Couple that with sharp diplomacy and you can get a crusade or two under your belt, and the map falls to your power.

It took several runs to get the sequences right, but the rapid expansion is still very, very effective, as I have now figured out how to accomplish in the VanillaMod as well.

The rapid expansion is based on sacking, low troop upkeep (not waiting 10 turns to take one city makes troops very cost effective), massive general spawning, crusades/jihads, cavalry, and possibly spies and artillery. It works against any conditions I have met so far. So long as you have a general, you have a blitz.