It seems the development team are not very enthusiastic about the idea of 1x1 PvP as they've been reluctant to even acknowledge the concept. Personally I'm rather neutral in regards to it - I hate the idea of open world unrestricted PvP (it is just an excuse for players to harass others as I've experienced this problem in other MMOs that have dueling in them), but, a restricted, tournament style system in the Colosseum or Gold Saucer could work, where the duel is separate from the main game and requires the player to sign up for it, thus preventing the harassment and e-peen problems open-world PvP brings.
As I understand it, this was the choice the development team had to face when designing the initial concept for the upcoming Heavensward expansion - whether to allow players to fly or swim, and they chose the former. Hence it's highly likely sea exploration and swimming will be added much later in the future.
SE are constantly adding new hairstyles into the game with patches - and with the new race the au ra coming in Heavensward, it's obvious new hairstyles and facial models will be added too. Just have patience.
Although a personal Limit Break gauge would just make things a little overpowered (technically this is what the TP gauge is for, at least in FFXI and FFXIV 1.0, but it was completely changed into ARR and no longer functions as such), in a way in Heavensward the level 3 party Limit Break will now be unique to each Job and no longer just be based on role, which is sort of what you're asking for. But true personal Limit Breaks don't seem to be on SE's agenda I'm afraid.
I agree. This doesn't include costume items or 'fireworks' that create the image of temporary wings on your character though.
I'm not sure about walking and running, but you can already change your character's pose when standing or sitting by simply using the '/changepose' command - each character has three standing and sitting poses. Additionally your character has an idle weapon drawn pose as well.