They have made quite a few attempts to make sure that we can solo just fine. FATEs, Levesquests, and Squadron Command Missions. I mean this games is a rather solo friendly compared to most MMOs, but since it is an MMORPG it is subject be focused on the multiplayer as that is what most people want to experience. The Trust system is just a concept that is borrowed from Final Fantasy XI since you could setup a party of Trust NPCs instead of a normal party, but this was to deal with the declining player population as the game got older since FFXI was older than WoW. I imagine that they will have some various limitations for the Trust system that will not devalue multiplayer. However, true single player is not something I anticipate actually happening anytime soon since some MSQ and side quests require 8 people, so you would need 7 trusts for that to make any content work. I don't think they are going to have that many for a while, but who knows. I will say that I loved the Trust system in FFXI so I hope it turns out successful, but I hope it doesn't ruin multiplayer experiences such as queue times or social connections.