It's going to be a pain in the ass to coordinate entering an instance, especially because all of the present content is on a timer. You can essentially be held hostage by someone on another server who's not ready, or enters the instance and is AFK. Yes yes, this can happen on the same server, but there are no repercussions for someone on another server.
I just have a bad taste in my mouth from the dungeon finder in WoW.... people will disagree with me, but I think it really degraded the community to something worse than it already was. FFXIV has an amazingly good community and if it were to take a hit because of this, I would have less of a reason to log on.
