What bothers me is alliance-based questlines. They need to be re-worked and overhauled to accomodate this change otherwise 70% of the story and core concept of the game will not make any sense. I firmly believe that all alliance "main" questlines should still be chained and played in the same order they are now, the only quests that should be freely available anywhere are the localized quest chains and fetch/kill quests that have no impact or relation to the main stories, as killing 10 mudcrabs in Auridon is no different than killing 9.5 mudcrabs in Stonefalls.
I am all for free Tamriel, but that doesn't mean the storyline has to follow that way aswell. For storyline to make sense, they have to be tied to zones where they make sense and done in that order. It also would work as a zone-guide, leading people into new zones and areas simply for the exploratory aspect of it.
This is what many people also believe should be done (including myself).
And it's not even that hard to implement, considering every zone already has an achievement tied to those quests.
Come for the necro, stay for the retro!