I'd like to suggest that you add "skill perks" into Book 2. By this I mean concrete, qualitative extras that you gain for raising skills to some specific cutoff.
For example, perks could be gained when you raise a skill to level 10, and maybe another one at 20. Examples of perks could be:
Dodge level 10: "Pit Fighter": When you are in melee range with multiple enemies, you gain a bonus to your dodge rate
Dodge level 20: "Devastating Counter": When you "unbalance" an enemy with a successful dodge, your return attack (if it hits) is automatically a critical hit
I'll admit that this idea is lifted from Elder Scrolls: Oblivion -- hardly old-school -- but sometimes great ideas are worth implementing even if they're new.

The real advantages of a skill perk system is that it gives the player both an interim target ("gotta hit 20") and a tangible reward for leveling a skill. Most skill leveling gives minor quantitative effects that are hard to notice; can you honestly "feel" that extra 1% chance to Dodge? But you sure could feel that crit you got thanks to the level 20 dodge perk! Anything that makes leveling more fun in an RPG is a good thing.