-why does the crusade/jihad caller even matter? Put your characters on a micro stack, land them on the target BAM there's your trait. If you actually think that a human player as caliph is any true advantage, i guess you haven't had the Pope as a vassal yet...no, crusader is VERY similar to mujahid. And please. Are you really saying that the byzantines are underpowered in the traits area? Born in the purple, August, castration, blinding, having the patriarch as a vassal right from the start... I would concede the point for other orthodox rulers, though. Still the autocephalous aspect of orthodoxy is VERY good.
- your point does make sense, but to think that a mere +5 opinion bonus to SOME rulers is actually the reason for their successes is a bit of a dumb conjecture
Summarizing, the actual bonus associated with with muslim denominations are at best +10 for the VAST majority of rulers. The penalties for half brothers (which are extremely numerous due to the multiple wives). Having the sayyid trait means a +10 bonus, but they are tied to already large dynasties which suffer from high decadence right from the start.
The problem with muslims is that they start on their highest potential right from 769. Their inheritance laws, which cannot be changed not even through factions, the free duchy revokation and the casus belli from certain cultures, which, when tied with islam, becomes very overpowered. When they are matched against the small and instable realms of early Europe, they're obviously going to be at an advantage
Just look a the problem here. The problem is not muslim rulers in general. The problems are the early starts, very specifically the situation in the iberian península. The byzantines are more than a match for any eastern sultanate (after the last patch, i'm actually yet to see them lose their war against the seljuks in the 1066 start). The speed with which the iberian kingdoms take land from the emirs in the 1066 start is astonishing, being very frequent to have a finished reconquista by 1100
No, the problems with the muslims are definitely not the traits. I don't even think that there is something inherently wrong with them. The problem here is having their best pitched against christianity's worse at very specific date and in a very specific region