This is getting a bit off topic, but poOlrane has had me thinking about his comments for a while now.
The pendulum does swing. There have been more than a few times (even recently) when the evil side seemed invincible, and with the right tactics, a lone Satho can still give even a group of good characters a good deal of trouble.
I remember the times when Arwenth was basically the only Crusader, and I was basically the only experienced Cleric (and not nearly as strong then as I am now) - and worse, our playing times only overlapped so often. Only recently, with the addition of a few high-profile recruits, have they become the massive force that they just weren't for almost the whole of 2009.
It's definitely true that a strong Crusader is very hard to kill, probably more so than a strong ranger or monk or cleric of whatever. Becoming a strong Crusader is yet another thing, and behind the current senior Crusaders are some intense and very skilled players.
Crusader amazingness, in my opinion, comes not just from the code - they have dedicated characters, clarity of purpose, and good roleplay; there just aren't many other guilds where every member has lined up so consistently behind the leader, dedicated to a common purpose. With that said, I think there are a few things Crusaders have that other guilds don't.
The big one, in my mind, is a natural companion guild. Even a very young cleric of Taniel can dramatically extend the lifespan, capabilities, and mobility of a Crusader, and the abilities of the two guilds complement each other well. This acts as something of a check on the Crusade (although I'm sure many of you will say it's not much of one, and you'd be largely correct) - but there are certain things that the Clerics of Taniel will not help the Crusaders with. Only a few of you can really appreciate this, but cooperation between the two guilds is not automatic... sometimes Luminier makes this require work.
But it's definitely a net positive for us - playing is more enjoyable when I feel useful, and their need for my skills means that I often do.
Perhaps there some ways to duplicate this effect this in other guilds. This would require, I think, some sort of "camaraderie bonus" for teaming with one's guild members - something like the Crusaders' "battle cry" ability, or perhaps even something that works automatically, to go one better. This would be a check on rogue characters (who wouldn't have these benefits unless they could convince their guildmates to join them) and on the Crusaders (who would have to deal with the combined might of buffed teams working against them, if they really start annoying people).
Perhaps another limitation is ability against undead. I think it's rather appropriate that not everyone has abilities to counteract them - and while Clerics of Taniel are easily the best at fighting undead, Crusaders are a very close second. If, say, the Shao-Lin somehow turned into an army of elite vampire hunters, then there would be someone else to go for undead removal services, and the Crusade would have to compete for the affections of players who simply can't take on undead themselves. However much grumbling there is among players about the excesses of the Crusaders, there is (and I would say should be) at least a begrudging acknowledgment of the work they do, and to the extent that this is really a problem, the only solution apparent to me is that other guilds have to deal with some of the problems nobody dares doing without a Crusader, whether they need additional abilities to do so or they can marshal what is already available to them.
In any case, I can think of a number of tasks I wouldn't do without a Crusader, a few others I wouldn't do without a Cleric of Taniel, and even a couple where I would certainly want a Ranger. I don't think that the monks or the clerics of Asral, to name some, have the same sort of "go-to" reputation, so there aren't quite as many reasons to make nice with them.
I guess this mostly concerns the various "neutral guilds" - how any of these proposed changes would trickle down to evil players, I don't think I'm knowledgeable enough to say. Still, I really don't want to reject poOlrane's concerns or others' simply because my experience with Geas is different from theirs, and hopefully I've said something useful here.