I love the idea of no flying as long as there are a lot of dynamic world events to participate in,
All sorts of neat little collectible shiniest hidden throughout the world, and a few puzzles and challenges to find. Oh, world bosses and what not too. I'd love to see rifts similar to Rift start to spawn up across the world too. I feel the no flying concept can be a huge success with enough open world content to compliment it.