I personally like the idea of training / education to aquire skills, and agree that this could be used instead of the current Nexus system.
Perhaps, and this is just my n00b thinking here, the skill levels could be linked to the percentage of failed items and losses in manu / pots etc. I don't know if it's possible to impliment in addition to the existing rules, but say the people who don't follow the apprentice path have a higher failure / loss percentage, and once you start on the apprentice path you increase success rates with reaching master level you have a 100 % success rate?
Just adding my 2p's worth