I like this. It should be optional though... just like perks.
Practice % - Training Potential
It sounds interesting, but I have no clue what skills you would be good at/suck at that would be balanced. I think there would probably have to be like 2 or 3 options per learning path...like a warrior could have the three towards the top of your posts. Clerics would have to have...I guess protective, healing...something that covers offensive spells and melee. I can't even think of anything for mages... Obviously you could only pick 1 and I guess would have to struggle with the others.
Edit: I don't find training that hard (maybe because I'm constantly hanging out in obscure places and have nothing better to do) so I'm not thinking that hard into this.
Yeah... to be honest, I don't really think training needs revamping. The skills/spells that are truly necessary for your class to compete are all things easy to do, for the most part.
Lets be even more honest...even semi-useless crap ends up mastered half the time. As far as c/c go...spamming = cheap easy exp. Melees seem to have a lot less useless things, and generally need more training. Eh...no fun, but you get the lovely little bonus of relying on your skill (plus a little dex vs dex fun) instead of praying to bypass saves.
Like I said, I don't think anything is wrong with training. But, a lot of people do. And, as the saying goes, "It can't be everyone else..."
But. Well, I just through this would be an interesting way to deal with the situation. (again, not that I think we need it) But remember, no bonus to skill damage or how they work other than increases/decreases training time.
As for mages?
Elemental -
Your interest in the elements aid your learning! - Burning hands, Lightning Bolt, Terra Shield, Air Shield, Icicle, Flame Arrow, Jet Stream. You suck at: Armor, Magic Missile, Sanctuary.
Holy....hrm.
Curative
You would rather learn to help than hurt: -Cure serious, cure blindness, cure poison, cure disease, refresh. You suck at: Cause light, Ray of Truth, Minding your own business on weekend mornings, Flamestrike.
It doesn't have to be allways "Offensive, defensive," or what have you, but something catagorical.
a-g
Hmmmm....quicker training for my elemental spells, or quicker training for Armor and Magic Missile? It's a toughie. 
the current system rewards persistence with perfection.
100% in a spell means you dont lose concentration and some spells perform exceptionally when mastered.
100% in skills means they land/hit/effect more and for more duration....
again...to excel you must be patient and dedicated, why would we want to change that?
I don't mind training at all. I write up a trigger (learn your mud client, give it a name, treat it nicely, take it to dinner and it'll teach you to trigger just about anything), I pop in a movie, put on the ps2, grab a book, or do something else...and I just look at my screen every minute or so. "Where" is a part of my trigger, and I do it often, so I can see whenever someone is coming up - not that anyone ever finds me where I train (one person, ever and they weren't even in my pk range, just exploring).
I suggest another perk:
idiot
You big dumb brute, you learn slower, but take less damage in combat.
Add another 5-10 hours for me to train, but give me a damage reduction similar to alcohol? I'd choose that perk every time.
Hmmmm....quicker training for my elemental spells' date=' or quicker training for Armor and Magic Missile? It's a toughie.
Oh bite me, you anonymous teddy bear, you. You know it was an example.. and you've always known my examples to be crap.
a-g
shrug I couldn't really care one way or another on this.
I just want to let Mya know it's not the rage that does wonders for training zerker weapons...it's going to the scarecrows and dual SWINGing for the fences.
I've played characters trained and untrained, and I can't say that it's ever made a noticeable difference in PK for me, EXCEPT when it's a really important skill like camouflage, OR if the skill was under 75%. Race, cabal, tactics and equipment all made vastly more difference.
Well I've always done better when trained. But then again, I think I have to rely on numbers and percentages more than skill yet. If I can't get the pk with wit and guile as easily... having everything mastered leaves alot of room for error. I guess it varies.