I was worried about this duty finder as well. Last night I was running around Limsa Lominsa for like an hour doing FATE's by myself with no other players to be found. A Free company mate made a great comment. "Well, we are suppose to be testing the duty finder during this period, so maybe a lot of people are just really trying to test the duty finder like they were asked to do."
I ran about 4 duty finder missions, and for the most part they went ok, but my cousin made a good point as well. Duty finder is nice for time's sake, but it will be mainly used for those who don't have many friends, don't have time, late night work shifts, and stuff like that that Yoshi-P stated. I think later on, the majority of the community will run with linkshells, and server players, rather than just rely on the duty finder.
It's cool, but partying with the unknown can become uncool, especially with no real reason to become social for the few minutes you guys see each other, and return to your servers never to see each other again lol. If you remember FFXI had something similar to duty finder, not as good, but similar and no one ended up using that thing from fear of who you might actually get. LOL
I had a friend who kept using Duty finder to do the Ifrit battle resulting in 6 losses. I eventually formed a party to my liking for him, and we went in there and knocked it out getting him the win. Like someone else said, other than saying hi, explaining the battle plan, and asking who's done this before... Other than that with the amount of targeting/pushing combos and such, not much room for talking during the fights. In FFXI we could talk through those auto attack tp building moments.