In reality, I don't like theorizing what the Hero is or isn't. That's almost like crossing a line... once we know what the Hero is really supposed to do, then the whole series will click into place. I for one don't want to be surprised about that one--that, and I really have no idea. Maybe I'll feel differently if I get a proper revelation regarding the Hero.
(And strangely, so begins my brain trying to create a revelation for it)
In any case, what the Amazon description successfully does is confirm that Ruin is the name of the Well-spirit, and that it is also the Deepness. We already knew this, but at least Brandon can't complain if I link new TWG members to the Ruin and Preservation topic. I always secretly thought he didn't like me for figuring that one out and revealing it to everyone.
Also, the blurb tells us essentially what Vin and Elend's plotlines will be, or at least foreshadows it.
Dying: There will be death. I don't know who or how, but people will die. I mean... we have an omniscent being killing people. That screams for sudden deaths.
I would say that it also mentions that there are earthquakes, but I really think that that is a topic for Ruin and Preservation (that topic is on Page Two, by the way).