I'm of the opinion that if you want something from a piece of content, you should have to do that content. If you are having trouble finding a group to do A12S then you will likely need to form your own. Personally, as far as poetics go, I dump all of mine into demicrystals when I'm at or near the cap. It's a quick 40k gil if you vendor them and I didn't have to do much of anything for it.