Aside from being end-positive in terms of investiture use, Allomancy doesn't seem too Preservation-y in itself. However, consider:
We saw in Tress of the emerald sea that steel and iron affect aethers in a similar way to how steel and iron allomancy work, pushing and pulling. If the aethers act this way with the metals, I think other things might as well?
We know from Lost Metal that the aethers predate the Shattering (if not Adonalsium Itself), and presumably, so do their interactions with metals.
Preservation's Intent is to keep things the same. It created Scadrial, but it's not creationist in itself; that happened when Leras wanted to make a planet with Ati and before he had been extremely influenced by the Intent. I'm pretty sure if given a void, Preservation would try to keep the void a void.
my theory is that Preservation powers Allomancy (at least Scadrian Allomancy) but didn't create it. I think Allomancy, or a version of it at least, existed before the Shattering, and Leras chose to preserve it by putting it on Scadrial when he created it with Ati. Maybe it was going to die out otherwise, or he had some fondness for it.
It would be cool to see a variant form of Yolish allomancy in the Dragonsteel trilogy one day, but I doubt Preservation would have made many changes to the version he put on Scadrial cause of his intent. At the very least, seeing Mistborn (not that they'd be called that on a planet that doesn't have the mists) fights in Dragonsteel is something to look forward to.
I've not yet read Elantris, Warbreaker, Shadows for Silence, Emberdark, White Sand, or any Stormlight after Oathbringer (have read everything else though!), so please don't spoil those; thanks.
