Sorry Ariel, but i completely disagree with your downplaying of the historical aspects of the keris. History is not simply a matter of the battle capability of a weapon or whether or not a weapon has drawn blood (though in some Indonesian cultures such as the Bugis the keris had a much greater use as an actual physical weapon. I also believe that the keris began as a true physical weapon, first and foremost and developed it's spiritual attributes as it evolved). A keris that is pusaka can hold the "history" of many generations. If i were to be the custodian of such a keris i would say that clearly the history of that blade is of utmost importance. At least it would be to me.
I would also say that contemporary keris are much more objects of art and much less objects of spirituality. The days of the Mpu is for the most part past and the magickal qualities that were once their providence to impart on the blades though fasting, prayer and magickal incantation are lacking in today's modern keris. Most keris are not made by Mpus anymore, only skilled (sometimes highly skilled) metal smiths who do not have the knowledge or priestly lineage to create such keris. I do not believe that is a reason to dismiss modern keris by any means, but i did want to correct your impression just a bit.
As an expression of high Indonesian art the keris is a living art form and though the keris does not hold quite the same cultural importance it once did it still has a place to fill in Indonesian culture. That is the difference that i see between it and the other weapons you mention and what i see as a real reason to encourage it's continued growth as an art form.
In my own collection i have mostly antique keris, but quite a few recent ones. I collect keris that i like, first and foremost. A blade need not be a master work to attract my attention, but it must hold some kind of character that attracts my attention. But with the antique keris that i have collected i am most certainly interested in that link to the past, that connection to history.
As for what is or is not a "fake", i would say that all depends on how it is presented. Artificial aging of blades is not a sign of forgery in and of itself. The look is a preference for many collectors within the culture. If, however, you age a blade and then try to pass it off as an ancient weapon, that is indeed fakery. As for the term replica, i am not sure how that applies to keris. Keris form is often set by certain pakem. So a keris that follows that pakem will, for the most part, look like any other keris that follow that pakem, regardless of when they were made. I can't see how that would make the newer blades "replicas", especially in a culture that still has a place for the keris in it's traditions and cultural practices.