A friend of mine on a Facebook Skyrim page asked me about something that I actually forund to be quite interesting.
He was upset about the ease with which skill levels can be bought from trainers. He suggested trainers issue task to be compleated a certain way, and that skill levels and spells be your reward.
For example, Sneak Training, the trainer would give you some potions and assign you a task to be completed in a limited amount of time. You have to steal an item and bring it to him-her. If you get it done using the potions and you didnt get caught, then you are awarded a few levels in Sneak.
For example, Magic Skill levels and Spells Training, the trainer would give you a task such as using a weaker spell ONLY to kill a certain NPC or beast, and if you pull it off you would be awarded a few skill levels and the next Spell stage in that form of magic.
I think you get the point. I would like to expand on this idea so as to include all skills and all spells meaning that you could not just pay money for spells or skill levels. This would be a massive undertaking to say the least. It would be a compleat overhaul of the training system and would include writing many mini quest for each trainer.