Some say its not a traditional Japanese art. Other's claim it is sport and not designed for self defense, still others have other reasons why bjj is not in the same category as jiujitsu in general. The best one I heard was that jiujitsu is about killing people, and bjj is not. Something that I find laughable the more I think about it. Breaking limbs, and choking people is most certainly as much about killing people as any other jiujitsu class I've ever attended.
The fact that the US Army has adopted it as the base of our combatives program should demonstrate a little I suppose as to the effectiveness of it as something other than sport.
I don't know to much about the koryu stuff and all, but can't say at the base level that I see any difference between this and any other art that I have studied. cept we don't tend to bow and meditate much.
I do think these things to be important.
Interesting is to check out Helio Gracie's book, it is pretty much basic jujitsu techniques that are common to all jujitsu systems. Not much on ground fighting, more on self defense, wrist locks,and arm bars etc from the standing position.