My crusades rarely seem to involve the biggest players, especially the HRE even when they are at peace. The king of poland loves crusading though.
Which I'm mostly cool with... since if the HRE or France joined every Crusade, they'd also win every Crusade, and they blob enough as it is. Maybe if the mechanics were changed and it'd create an independent Crusader state of the winner's dynasty if they're a king or above.
Even having a medium kingdom like Sweden or Poland help out can be huge, though. I've definitely seen successful Crusades against the Fatimids where we didn't have the support of one of the bigger powers, and typically it was due to a combination of the Pope not being a complete tard with the timing and hitting the Fatimids when they weren't at full strength and some of the participants not being completely worthless in terms of manpower. Heck, in one game Venice of all places won Jerusalem (thus creating The Most Serene Republic of Jerusalem... yeah, "serene"...), thanks to their massive merc stacks.
All boils back down to blobbing, though. Crusades are difficult simply because the Fatimids are disgusting in their ability to do so (though they SHOULD be hard, Crusades should never be easy), and often times the succeed simply because a Catholic power just as disgusting in blobbing ability actually lended a hand, and thus blobbed a little more.
