Yeah, I've never bought one of these either. Has KOS-MOS always been sold by the tits? :/
While, as a constituent of the heterosexual male demographic, I am obligated to note that titties are important, I also have to admit that none of Xenosaga's promotional material that I've seen so far looks even remotely appealing to my eyes.
True, I wasn't there to see how the games were actually marketed at the time of their release, but the stuff on the games covers' and cutscenes viewable online hits about the half of the things in my persanal list of 'visual design hailing from modern japanese popular culture export' dislikes.
The only reason I've found Xenosaga was because of deliberate trawling of tvtropes in an attempt to see if something out of all the stuff in the JRPG genere I've missed would be something I'd like to play.
Closer to the subject of the thread, I'm afraid I'd have to agree with Jintoki's assessment above. The first game gets simply too tedious to play very fast.
Sure, it's done in my favourite style of 'sprites on a 3D background' with a surprising amount of attention to detail in both said backgrounds and character animations, but, IMHO, eye candy can't carry mindnumbingly repetitive gameplay all by itself.
And that's exactly what it has to do. Both Xenosaga-related segments and other games of the mix that I am familiar with don't really have anything going for them plot- or characterisation-wise besides 'oh, I know that character, wait what do boob jokes have to do with anything?'.
I have yet to play Super Robot Taisen OG Saga: Endless Frontier, but I strongly suspect that this would be the case for that game as well.
This is awesome news, of course, but I'd like something a bit more thought-provoking than an ultimate showdown of ultimate awesome. And more Ziggy, please.