Imagine the scenario where you have a high level champion focusing on strength, and another high level champion focusing on dexterity (for dodge). Even if the chance to dodge increased by 2 per level, the champion focusing on strength would have zero problems hitting the swift champion because accuracy is purely a determinant of level.
This creates the odd scenario where a high dexterity champion is capable of dodging low level enemies -very well- but nothing else. This can effectly make fielding armies pointless (for addtional reasons).
Accuracy and Dodge should both be based on encumbrance adjustable by traits.
Encumbrance should not be a mutable stat. Heavy armored units are -supposed- to be encumbered. They hit less often and dodge less often, but take less damage. Encumbrance should have multiple levels to it - 4 would make sense. <25% (none) grants bonuses to dodge and accuracy, <50% (light) imposes penalties to spell mastery/damage, <75% (medium) imposes penalties to accuracy, dodge and spell mastery/damage <100% (heavy) imposes penalties to accuracy, dodge, spellmastery/damage and move.
Traits could be greyed out based on encumbrance level. That is to say a medium and higher encumbered character would not have access to fast, and only an unencumbered character would have access to charge. Traits could be used to adjust encumbrance as long as there is an appropriate trade-off. Let's say for example going from medium to light removes a penalty of 2 accuracy and 1 to dodge. The 'accuracy' trait of 3 makes removing a level of encumbrance not necessarily the most appropriate option.
If accuracy is adjustable by level it should be by a -very small- ammount, so that relatively equal level units will have a relatively equal chance to hit each other.
The functions of strength, dexterity and constition may need adjusting, as well as some items, and to prevent gamble mechanics, champions may need to start using multiple attacks, but that isn't the scope of this discussion. Basically I'm looking for ways to make the level disparity less harsh and encumbrance a larger factor in design.
Just to throw some numbers out there, assuming a forumula of (Acc/(Acc+Dodge)) to hit:
Base Dodge is 5
Base Accuracy is 10
(Base to-hit is 66%)
No encumbrance Provides +2 Accuracy, +1 Dodge
Medium Encumbrance Provies -2 Accuracy, -1 Dodge, (and -30% Spellmastery/damage)
The unencumbered unit would have a 75% chance to hit the encumbered unit
The encumbered unit would have a 57% chance to hit the unencumbered unit
In this way it would still be more useful to wear armor to defend against physical attacks, but in those situations where unit defense was unimportant, such as with first strike, charge barbarians, or archers in the back row, you would want to maximize your hit rating and wear less armor to do so.