Unfortunately due to how those zones have been designed it's frankly impossible to implement flight in them - not only are they very small (meaning the speed of a flying mount would reach the border too rapidly), their backgrounds are designed only to be seen from certain angles, which would make them look downright artifical (like a theatre set), which would thus necessitate a complete rebuilding of those zones from the ground up, which is quite frankly more trouble than it's worth. It's not impossible for SE to do, but as they increased ground mount speed to double what is available in HW/SB areas to compensate for not having flight in ARR areas, I hate to say it but this simply will never be happening.
We technically already have this, with the treasure hunt and the mobs that spawn from them (and Aquapolis which is connected to it).
They already are rather large, and as for scaring new players, given Yoshi wants this game to be accessible to new players, he will never do such a thing.
Again Yoshi wants this game to be accessible to players of all persuasions and abilities, including casual players who have never played a MMO before, and he does not want new players to be unfairly targeted by high level players if open world duelling was available. The closest you will get to open world PvP is the Duelling Circle at the Wolves' Den (and given how little used that is, it's pretty telling to SE that open world PvP simply is not widely wanted anyway).
People have repeatedly asked for the GCD to be reduced since the Beta test and he's outright said "no". So this will not be changing I'm afraid (it's not that slow, WoW players are just being melodramatic, and before you pass judgement, play FFXI: that has a really slow autoattack and ability cooldowns that can be as long as an HOUR (in it's heyday, a whopping two hours).
Again they will not be implementing open world PvP.
Uh, we already have Ruby Carbuncle? Wait for SBS to be launched, as the level cap increase is bound to bring new abilities (such as summon spells) for SMN, if not actual egi glamour.
I think that airship has sailed I'm afraid: CNJ gets the unicorn and tanks get achievement mounts as a way to get people to stop just going DPS and actually levelling and queuing for content as healers and tanks. Of course nothing is stopping him doing so, but I doubt it will ever happen.
Again if that would happen it would have been done so when the class was first added. Besides, think of it like the classless Jobs - you need to level an earlier class to unlock it (and given ROG's secretive nature lore wise, it makes sense you just can't level it as a brand new adventurer just off the boat).
Uh, this was one of the reasons we got ARR in the first place - 1.0 with it's huge zones and cities that were directly part of them had so many issues that only scrapping the game entirely and rebuilding it with smaller zones and cities as seperate zones could fix it. An example of what I mean was in 1.0 when inns were added: players idling in the Quicksand broke the Inn so completely SE simply could not fix it. Instead, to ensure the servers remained stable (in a manner of speaking) they were only able to implement a backdoor in another part of the city with a npc that allowed access to it, you could not enter the Inn at all in the Quicksand in 1.0, and that remained right up until 1.0 got it's well-deserved bullet behind the ear.)
And as the problems with such huge zones was one of the biggest and loudest player complaints about 1.0, again SE will not be changing this (although Kugane and Rhalgr's Reach are both single zones so that might be the closest you will get).
Again, this was for technical reasons, due to players tending to idle in those areas, in ARR Revenant's Toll became somewhat laggy and so SE made sure not to make that mistake again. Hence from now on every place the 'end game gear' vendors are located, will be in a seperate city zone and not a regular hamlet out in the boondocks. It's to ensure server stability.
I'm pretty sure SE cannot do this due to how the music is programmed in the game - certain music tracks are queued up to play at certain times and at certain spots in a zone - the Orchestrion on the other hand is a seperate track that technically mutes the normal BGM in an Inn or a FC/private house/apartment, which would be too complex to implement in zones with multiple queue points for multiple tracks that need to be played immediately (like battle themes). I agree it would be awesome to ride along on my Legacy Chocobo and queue up Answers, but sadly, I doubt Soken will ever be able to do it. It would be great if he could though.
A bouquet rather than a brickbat for a change - I admit I like this idea and don't know why SE hasn't done it already, as it is indeed a standard RPG trope.
Even if it would get a bit repetative after a while.
I'm sorry if it seems like I was shooting down your wishes, (the ones I didn't answer are actually your ideas that I agree with), it's just that many of your ideas have already been mentioned by others in the past only to be given counterpoints by Yoshi and SE as to why they can't or won't be implemented sadly.