Okay, let's try this:
A new system for rewarding RP and perhaps a new system for trains/practices/proficiencies.
And we'll toss in Croyvern's idea of 50's only being able to "master" so many skills.
So, how about as you level you get your trains and practices, but you have a "path" within your class that lets you choose which skills/spells/songs you want to be able to push beyond, let's go with a range between 95 and 99%. Just pick any number in there you want that you can't go past for your non-50 mastery skills. Now, I know this currently sounds like a mess, but it's a rough idea.
Now, also, every other level you get an "insight" bonus you can choose to prac 1% or 2% beyond 75. Now, this isn't a regular prac, but a prac for the "insight" prac, so it's separate from a regular prac, different slot for it.
Also, I know we're not trying to "speed" up training, but let's face it, training is boring. So, on top of having this "insight" prac, how about when you fail a skill it goes back to randomly increasing between 1-3%?
Now, on top of this, instead of IMM bonuses for 50's being given random advancements, they can give them these "insight" practices.
Rip it apart as you please. I have a synthesis paper to get work on.