I really have to read the rest of that fic - read the first half or so of it when that's all there was, since it finished I put the rest on my kindle but haven't gotten to it yet. I am a fan of both Dresden Files and WTNV, so it worked for me on that side, and I think the version Carlos in particular worked for me because on the one hand he's a total badass fighter and wizard, and on the other he spends much of time completely out of depth and desperately struggling to save the day.

(also, apropos of nothing, but voluntary recreational intoxication being a squick for you, ahh thanks for laying it out like that, it made it jump into focus for me - I don't know if I'd say it's as strong as a squick for me, but considering how much I love non-consensual or accidental intoxication in fic, recreational drinking and drugs leave me totally cold and generally frustrated...)