As much as I enjoyed everything about Xenogears, I really hope that doesn't get a revival. I can't imagine a different story to provide as much character involvement/development to it, nor gameplay to be improved upon (though that one could pass with a generic reuse of it). Unless the impossible is achieved, it'll just feel substandard by comparison. Xenosaga was hit or miss for a lot of it.

Personally, I'd enjoy a continuation of Einhander, as odd of a wanting as that is. I guess it's one of those things that you really can't go wrong with as it's mostly focused on gameplay than anything else. It'd be pretty comical if someone were to take up Bouncer though lol.