Good day all. New to this forum, so pardon any unintentional faux pas on my part.
Without a more solid foundation than speculation (no matter how well thought out!) for the theory that Ruin/Preservation may be directly linked to one or more of the Power systems of the land, I find it difficult to ascribe such a linkage. Granted, if one exists, it would surely be between Ruin and Hemallurgy, given the deadly and bloody nature of gaining access to this Power system. I do find it plausible that the events of Vin receiving the brass earing could qualify as a sacrifice fit to confer Hemallurgy upon the recipient, and while the parallels are there, no textual hints or foreshadowings that such is true can be found.
I enjoy and appreciate the theorization, my problem is that I am a technical analyst by nature, and more likely to apply Occam than to stretch out with potential theories. The things that are known without doubt are the existence of the three Power systems (Allomancy, Feruchemy, Hemallurgy); the mists, which are governed by a force which TLR kept at bay (presumably by a hybrid application of all three Power systems); the being at the WoA, which Rashak (rightly?) chose not to release upon his ascension but which Vin freed.
The being at the WoA is not directly tied to the mists, since the mists began advancing after TLR's demise, including selectively causing deaths of some, but not others; and this is before Vin releases the being in the Well at the end of MB2.
I believe there is good confidence for the idea that the Inquisitors' allomantic abilities and superior steel sensitivity are a hemallurgical trait; that there is strength to the theory that a malevolent force (Ruin?) can touch those who have hemallurgical attributes (Zane's 'insanity', Marsh's need to take actions he can't explain and wouldn't normally approve). But I would sooner think that the Inquisitors' remarkable healing ability is a function of hemallurgy's affect on pewter, than a connection to a more spiritual force.
Some speculation has come up regarding potential differences between the noble class and the skaa regarding access to Power systems, which I would reject. Elend spent a great deal of time and effort to prove to himself, and later the rest of the nobility, that there was no real difference beyond the favor of TLR. That effort, as a major sub-theme, is wasted if there are real differences. Given Elend's transformation at the WoA, it seems likely that Rashak granted the same to his favored friends after his ascension, and made laws prohibiting interbreeding with those outside of his favor, establishing the separation of classes among the people. A thousand years of breeding diluted the noble class to the point that being an Allomancer became rare, and Mistborn extremely rare.