The map is called "heat map" and identifies which are the areas for low/medium/high rank players. The trainers are following the same heat map.
Hydlaa is the place where everyone spawns (at this moment) and it's the place where low rank trainers are located. The other cities, like ojaveda and gug are considered still low rank, but players will not reach those immediately, so they have a bit higher rank trainers. The most dangerous and high rank area at the moment is bronzedoors.
This distribution will allow players to find other similar ranked players in certain areas, which facilitates groups and discussions.
As for the roleplay aspect of trainers being capable of training up to their max rank, I may agree, but if we apply this means in bronzedoors everyone will train everything from 0 to 400, which will put those NPCs under real stress! They don't want to train a bunch of newbies, they have to look out for invasions and find the best fighters.
When we will have 2000 concurrent players as an average, we will have all racial cities modeled and our cities will be fully populated at all times, then we will probably go back to a system where each major city trains the basics, so enkis can stay in oja, kran in gug, etc...