Trainers of any kind have yet to been descussed, so they have not been confermed. However, one could assume they will be in game in some shape or form if looking at the past two are any indication. Now, what I am sugesting is instead of simply paying for the skill increase, one would actually go through the training exercies.
Needless to say, this could get repetative and redundant. That is why I'm limiting my sugestion to master trainers only. I'm not talking mini games either. Say you find a master of one handed combat, he could choose from a range of one handed weapons and the goal for one level would be to strike a blow against him, or to push him back. He could coach you on how your fighting, possibly giving advice on if you're butting mashing instead of fighting with tactics in mind or if you're to tentative with attacks and you're not being agressive enough. A master of destruction may find another aprentice for you to duel against. Nothing to the death of course, but training. In a world where you get better at something by doing it, it is my opinion that training with masters should be no different.
A master marksman could place a target downrange and have you stand 50 yards back, and for the level up one would need to hit the middle most ring of a target.
And finally, masters should have an active impact on the world. They're on par with us for a reason, they're good at what they do. Maybe not all of them, but a few may choose to live active lives in towns. If you enter a town and ask for the best place to buy swords from they'll point you towards the master smith, not point you to him only now that you've reached lvl 70 in smithing. Rumors floating around may be that a master of two handed weapons took down a dragon in the town over, only to disapear right after killing it.
A theif may have just left his signature where a sword that had been passed down in a royal family for generations used to sit, the strangest part being that the signature hadn't been seein in a long time. After tracking down the theif, you find him to be a pupil of a master thief.
I guess what I'm trying to say, is that master level people shouldn't be treated like ordenary people. They're on par with the dovakiin, or the champion of Cyradil, or the Nerevarine, and should be treated as such in my opinion. Characters walking buy them should show some form of respect, especially if they hold the masters skill itself in high regards. Children especially should be in awe of people that are master class. Also, for us masters should feel more like teachers. They're showing us the ropes, and a few ingame quests could be fun, instead of just paying the bill to level up.
What does everyone think? WIll master class people be treated differently? Should they be?