In my last game as Ireland, crusades were quite effective. I saw jerusalem be formed and lost to jihads about 3 times. On the 4th one, i sent troops to alexandria and cairo to make the fatamids armies detour. Was effective and while they tried to get my running armies around egypt, the pope's army got most lands in jerusalem which resulted in the catholic victory. For some weird reason, i won the crusade and jerusalem was mine without a single battle or de jure siege won.
All in all, the first crusades are the hardest to win, after holy orders come around, it gets easy to small players get the hang of situation, like my Ireland.
All in all, the first crusades are the hardest to win, after holy orders come around, it gets easy to small players get the hang of situation, like my Ireland.