In the context of an RPG some things are obvious. Dexterity determines how well you can dodge attacks, Constitution determines how much damage you can absorb, Strength determines how hard you hit with weapons. But what good is being smart? In most systems the answer is absolutely nothing. Being dumb as a box of rocks or a trancedent genius does not change a person's odds of winning a fight. This isn't so outrageous in some contexts like a strictly controlled sword duel where practice, reflexes, and strength should be the determining factors. However, in a messy brawl against unknown opponents in a unfamiliar environment while dealing with surprises and unexpected twists one would think that being clever would really matter.
So now in Heroes By Trade Intelligence gives you the option to alter events that have just happened on the assumption that you planned for them or reacted perfectly.
"Aha, you could never have planned for me to have a hidden dagger in my boot. Now you are doomed!"
"Afraid not good sir. I thought of that and hid a dagger in *my* boot as well!"
I want to call this ability Anticipation. Normal people wouldn't have it as it would be restricted to people with 7 or more Intelligence and a regular person ranges from 2-6. The advantage to having even more Intelligence than that would be increases uses - one use per encounter at 7, two per encounter at 11, and three per encounter at 15 Intelligence. So what good is being smart? It makes it possible to plan ahead for a particular move and ensure that it works, or to react instantly to a disaster and avoid it. That, to me, feels like exactly what a smart person would be capable of doing in a unpredictable and dangerous situation.
The nice thing about this is it lets me get rid of the previous kludge I have been using to make Intelligence useful. Previously I had Intelligence determining how hard it was for enemies to hit you with spells. Now I can eliminate that mechanic entirely and instead of having Dodge/Armour for physical defenses and Ward/Resist for magical defenses everything can be under Dodge/Armour. It simplifies the list of defenses and since that added very little strategically but a lot in terms of number crunching I like the simplification. There is only so much complexity you can have in a game so it is best used where it is most interesting and fun.
One other fun thing to fall out of this design change is that the damage types that classes have can be a lot more varied. I wanted to keep each class strictly magical or physical before because otherwise there would be a lot of confusion with keeping track of what target numbers were and what damage types were being used. Now with consistent defence values regardless of attack type I can have Thundering Charge actually do lightning damage if I want and Meteor can do physical when the meteor hits and fire when it explodes. These things generally won't matter but thematically it pleases me greatly.