I only played 1.0 for a very short time right at the end of it's life and A Realm Reborn legitimately beats it in almost every category...almost. I'd even venture that with a single improvement, it could become the best MMO.

Area Transitions. It's 2015, people want realism and that comes with one big open world like Assassin's Creed, Grand Theft Auto, etc. Transition/load screens significantly draw away from realism. After having played A Realm Reborn/Heavensward for almost 2 year since it was released on PS4 I still haven't completely gotten used to it. I find it particularly sad that it still doesn't have the seamless transitions between areas. Especially considering the power/capability of the company behind the game.

Make Eorzea one big open world with no load screens between areas (or towns) and it will be without equal!