I think that Zorn's eclecticism sometimes comes off to some as sounding like he's trying to please everybody, or like he's tip-toeing around what he actually is trying to say. I don't share that viewpoint, though; I think that Zorn's musical character is defined by his oddball compositional and improvisational style, as well as his radically varied "genre" output. Some call it "trying too hard", but I rather see it as simply what he does best. Don't forget how much cartoons influence his work; the spontaneity of his biggest influences can just as likely parallel the absurdities of his work and the variations.
I do share your views regarding the number of Masada releases, however. While I do highly favor the number of different arrangements Zorn has integrated into his Book of Angels compositions, I am not so impressed by the fact that the four piece Masada arrangement has released easily 5 live recordings, all of which contain many repeats. But hey, maybe Zorn and company just believed that they needed to "update" their previous releases. It is inarguable, after all, that early Masada and later Masada are very different. Now, on the other hand, we've recently been seeing many different adaptations of the Book of Angels compositions, such as with Marc Ribot's Asmodeus, Electric Masada, and The Cracow Klezmer Band. This stuff, to me, is really cool, and I've enjoyed hearing the freshness behind these new renditions. Seeing somebody like Erik Friedlander, or Jamie Saft, attempting to re-work them in even more unique ways is simply a blast.
It is clear to me that Zorn does not easily escape his love for metal music. He was only able to abandon it for a short time while he heavily focused on the Book of Angels... he's back again with the Moonchild arrangements (which are definitely reflecting a love-hate relationship among fans and casual listeners alike). I really enjoy these and I hope that he pursues them further (but maybe minus Mike Patton?). I may end up voting for this category of works, but right now I cannot deny the effect that Cobra has had on me as a musician. This is a tough decision...