Here's my suggestion.
I think the all attributes attribute to Fortitude, Reflex and Willpower spreads the other effects of combat stats around attributes a bit too thinly. I think Damage, Accuracy and Health/Stamina are equally as important (if not more important) than defenses.
Here I propose a system where Damage, Accuracy, Health/Stamina and Fortitude, Reflex and Willpower are considered semi-equal for this proposed system. The defenses have been placed with higher efficacy secondary combat stats.
Attribute #1 (Might?) - Damage, Healing
Attribute #2 (Perception?) - Accuracy, criticals
Attribute #3 (Constitution?) - Health/Stamina, inventory size
Attribute #4 (Vigor?) - Fortitude, hostile effect reduction
Attribute #6 (Dexterity) - Reflex, Action Speed
Attribute #7 (Resolve) - Willpower, Durations, AoE Size
Might increases damage and healing - healing could mean Stamina Regeneration and adding the same amount of "damage" to Healing Spells, so any class with a flat heal also benefits. Stamina regeneration only occurs from ability/spell use in combat for all classes other than Fighters. Fighters in PE don't really need damage, but if the increase in Stamina Regen is good, then this would be valuable for them.
Perception increases accuracy and does something to augment criticals, this might be increasing the critical damage or making criticals easier to get - but it should not have as huge of an impact as it would in PE's current system as it is the secondary effect of the attribute.
Constitution increases Health and Stamina, which are gained at the same rate. I think it's better to keep Health and Stamina married because it is a more intuitive system. I think the Health & Stamina ratio is a more interesting mechanic, and perhaps the game could include a "Toughness" talent that reduces the Health Damage taken by 5% or something - giving a small taste of Barbarian toughness, but they could also take it to be even tougher.
Vigor is the best name I could come up with for this one, but is essentially the character's resistance to ailments and such. It increases their Fortitude defense, and reduces the duration of hostile effects. This could be a percentile reduction. I think this would make for an awesome attribute with Fortitude and effect reduction, as Fortitude on it's own is boring. If this became an attribute you could bump the durations of all effects a bit to compensate.
Dexterity increases Reflex defense and Action Speed - this includes all actions such as attack speed, cast time, item/consumable use and reloading and has a percentile reduction on the "downtime" between actions. This would have to be kept finely granular as to not be overpowered, but I think it is a better representation of the Dexterity attribute this way.
Resolve is essentially exactly the same as Josh Sawyer proposed, except the effects on Durations and AoE size are not as wide as previous, because it is the secondary combat stat to improving the Willpower defense.
I think that's a pretty good system tbh and even more intuitive than the current one, but if you'd prefer that all attributes add to defenses then that's fair enough. I just think that Damage, Accuracy and Health are equally or more important.