If I could have been Bethesda's adviser, I would suggest something a bit different.
IMHO, the first town/area that the players start the game, should have all the needed vendors, teachers, challenges, loots, and facilities needed for the players with the most classic game-play styles, like fighters, sneakers and mages...
But all those aspects should be related to the general difficulty level of the area, so in the starting area, the difficulty level, therefore, all those aspects should be suitable for newbie players, and the more the players diverge to the higher level and more dangerous places, the more challenge and reward they should find.
So in the initial newbie area, they should find all the vendors that any play style needs, but always, in all those vendors there should be only newbie items for trade, except for the rare chances of some higher level items, and the vendors should have little money to spend.
The challenge level of the initial area, should also be small, so you would encounter only lower level monsters, except for the rare chance of a bit higher levels ones of-course, and the reward/loot should be scaled to the challenge level.
The starting quests in the beginning should also initially be simple to solve, except for the ones that would eventually lead the players to the more challenging areas of the game.
This way the newbie players should be comfortable for a while, and all their needs would be answered, regarding the needed facilities and excitement of challenges, and the rewards, but as they grow in power and confidence, they would feel the need to explore the game for more rewarding challenges, and would start to diverge to other places/holds.
In those places, the cities should have higher level vendors and facilities, needed for higher level players, with higher level items for trade, and higher pocket money, higher level locks to break into, and higher level monsters and rewards, but newbie players would not be advised to travel there before they are ready for the challenge level.
This is the ideal topology for the challenge/reward level of the open world role playing games in which the players would gradually grow in power, and could explore more areas for adventure, so Riverwood should have all the facilities needed for any main style of game-play, but vendors should have low level items for sale and little money to spend.
The surrounding dungeons should also have low level foes with little loot, except for the bosses and some some chance of rare champions in the middle.
The woods should have low level animals and monsters, with their low level loot, with a small chance of higher level monsters to spawns that could force the player run toward Riverwood to let the village guards kill the rare higher level monsters, and town/village guards should be quite a bit higher level than general difficulty level of the area.
Whiterun and its immediate surrounding area should be a bit higher level than Riverwood, but not much and vendors should have more money and a bit higher level items, with the rare chance of even higher level items, but the vendors should not be high level in exotic specialized items, and the teachers should not be master of exotic specialized skills.
But the more the players diverge to the more exotic and secluded places around the game, the higher level the towns' facilities should be and the more specialized the vendors should become, with more money to spend on their specialized trade, and so on...
The immediate surrounding areas of the cities should always be relatively safe, but in higher level holds, some nearby tricky dungeons could exist, and the chance of some rare ambush of high level monsters/foes, and so on...
So in Winterhold for instance we would have the highest level traditional spell merchants, but if the players want more exotic spells, they should have to find them in other more exotic places, like a hidden necromancer den deep within an undead dungeon for instance that the players could find and try to befriend to be able to learn exotic high level necromancy spells, and so on...
Riften should be the center of high level tricks for the sneaky characters, but if they want to learn the highest level tricks, they should run errand to the grand masters of the tricks, only found on more exotic hide outs, much like the master level errands of the trainers in the College of Winterhold, but those master level errands should be given to the players in more exotic and hard to find places than a hold capital, and the hold capitals can provide expert level teachers, errands and rewards.
Markarth, could be the center of actions for the fighter style players with centralized higher level teachers, errands, and tricks to be learned, but as always the best tricks should be learned after the master level errands, provided for the player in more exotic places than Markarth, itself.
All the hold capitals should provide low to medium level vendors/facilities for all the different types of play style, but each town/city can be more specialized in some trades/tricks and provide higher level service in those areas of expertise, with more specialized vendors who have more money to spend.
This way the initial area, Riverwood, would be a perfect place for newbie characters, and the central hold, Whiterun, would be a perfect for low/mid level ones, and after that in order to specialize, and find more exotic teachers/vendors, the players would have to choose the place they would want to head toward.
OK this was my idea of a great open world role playing game.
Also I think almost all the higher level perks should require the players to seek the needed skill master for the trick, to become their apprentice, run their errands, and maybe even pay, to learn the trick/perk.