+1 for different text & animations dependent on the attack roll and armor type
I think it should have an element of randomness for variety's sake, e.g. if the enemy rolls between 10 and AC-1:
- Light Armor: 80% chance your character dodges (text says "dodged!"), 20% blocked with armor
- Medium Armor: 50% chance of each
- Heavy Armor 20% dodge, 80% block
- Shield: If the player is wearing a shield, they block it with the shield 30% of the time, appropriately subtracting ^ percentages
Something like that. This way both Dex and Armor feel effective. Larian could also add in a percent chance for parry if the character is dual wielding or using the parry ability, etc.
Alternatively, Larian could do exact calculations where if the attack roll is between 10 and the armor AC, it hits the armor; if it's between the armor AC and the Dex bonus, it's dodged, etc.