Destructoid have released a preview about Elex. In it, the editor gives his impression about the game's very open world, among other things:

Much to my surprise, ELEX is possibly more open-ended than Zelda. You’re given total freedom to explore any area of the game. If you see a distant mountain, you can travel to it. If any of the NPC’s look at you wrong, you can kill them. If you feel like giving the middle finger to the main quest, go right ahead. The game world will compensate for that lack of quest giver and allow some other option for progression. That sounds an awful lot like Morrowind.