When the author of the Ars Arcanum says that Hemalurgy is interesting and has possibilites, he seems to imply that it could be used to steal other powers. My issue with this is, that would it have to be a person with the spiritual DNA from Scadrial? Or could it be any place that Ruin has been. It seems insane that Ruin's magic system could work throughout the entire Cosmere, but that is why I feel like it might. It is the power of change and change is always happening. However if this was going to be the case, would Hemalurgy have to have a different focus on each planet or would metal work on all of them. So far it is the only power that we have come across that is not bound by a person's spiritualDNA.
On a side note, I feel like Hemalurgy could steal the spiritual DNA that allowed a person to use Breath, attract an Honor Spren, or possibly even become an Elantrian if the correct DNA was stolen, and you had Sazed or maybe Marsh to show you the bind points.
Also is there any reason that Bloody Tan could not have seen the real Kelsier? He was hanging around, and though Sazed was not able to reach out and get Vin and Elend, Kel seemed to be much more accessible. Crap i am really off topic.