The trust system in FFXI can be used in the open world and dungeons, not in cities though. I suppose it makes sense to limit this to dungeons due to the way FFXIV is set up. It works great in FFXI though, with good synergy between trusts especially if they have ties to each other in the story. I doubt we'll have to go through the process of unlocking more than 3 trusts to summon at a time, and I hope that trusts can be unlocked by the main quest as opposed to having to hunt down their ciphers to trade to the Trust npc. If they do use ciphers, most trusts are unlocked by using the free login points FFXI players get by login in 1 per day in addition to a few unlocked on the side of the main story.