A player being drunk is just like anything else. If they're holding you back that badly, that's what vote kick is for. I've only had problems twice with people so drunk that they couldn't actually function. Once it was a healer that was so drunk she couldn't even keep me standing through normal trash packs in AK HM. The other time was a dps that kept saying 'brb beer' every 2 minutes. Both times we kicked and replaced and were fine. Hell, my static's BLM was hammered so badly he was barely coherent on our first T12 clear (static was done for the week, and we happened to hit him up to join the group only minutes after he got home from a night at the bar, lol).