On the first thing you mentioned, SE has to be very careful how they alter the repair NPCs. The repair NPC mechanics and their implications are not an island unto themselves. It's a balancing act between the objective of using it as a gil sink, and the objective of fostering varying sorts of commerce between players.
On the second, I've heard that said before that they should make the teleport cost gil instead of anima. That, with all due respect, makes little practical sense if you are contemplating a world where chocobo rental and airships also exist. Why would a rational person use a chocobo or an airship to get from a city to a camp when (still assuming that gil is easily acquired) they could just throw money at an instant teleport? If you presuppose gil is worthless in the sense that it's easy to acquire, than there is no real opportunity cost to choosing the instant teleport over the other two methods of travel which are not instant. Why would I or anyone choose a less than instant option when all three choices are equally valid otherwise? The answer could be "because you could take chocobos from the camp that you teleported to to the place you're actually going". That's a different system where the other forms of transportation pick up where the teleport left off. If you are talking about something like that, then they all work in harmony offering a continuous transportation network from your point of departure to your ultimate destination. Otherwise, given where the current airship docking points are pre-placed and that the chocobo stables appear only in cities... I don't see the logic in making it cost gil instead of anima without devaluing the other means of transportation to a point where they are nearly unused.
RMT will be RMT regardless. They're clever and they have their own incentive (to earn a living) which will drive them harder than SE's own drive to eliminate them. Spending all of your time and energy playing kill the RMT just makes the game less enjoyable on the whole.