This is my understanding of NWN2 and BGTSCC as-is (note that Mighty property only affects damage dealt, not the attack roll):
Damage: All melee and thrown weapons (including slings but excluding shuriken) are Mighty +999 meaning your strength modifier will increase or decrease damage dealt, down to a minimum of 1 damage after strength modifier. Bows are only Mighty +0 by default, meaning strength penalties will reduce damage dealt, but a strength bonus will not increase damage dealt unless the bow is Mighty +1 or more. Crossbows by default are NOT Mighty, meaning your strength bonus/penalty will not affect damage dealt (making them good caster backup weapons) unless they have the Mighty property when examining them.
Attack: All non-finessable melee and Brutal Throw ranged weapons (except slings) modify their
attack roll by your strength bonus/penalty, whereas one-handed melee weapons with
Weapon Finesse and ranged weapons (with or without Brutal Throw feat) modify their attack roll by your dexterity if it is higher than your strength.
My suggestion:
What I propose is that Brutal Throw should include slings, so their attack roll can be modified by your strength if it exceeds dexterity, similar to the other thrown weapons, to better align the feat with
NWN2 Wiki.
NWN2 Wiki wrote:Thrown weapons: darts; throwing axes; shuriken and sling (while technically a projectile weapon because of its need for ammunition, the sling is considered a thrown weapon in game mechanics)
Currently Brutal Throw feat does not treat slings as thrown weapons on BGTSCC, which may cause players some confusion since this is counter to NWN2 Wiki which I am sure many BGTSCC players refer to. Testing this in-game, the BGTSCC combat log and character sheet seem to agree with me; an 18 STR and 10 DEX level 1 human Rogue with Brutal Throw feat has a +4 attack bonus with darts but only +0 attack bonus with a sling, even though NWN2 Wiki considers it a thrown weapon.
If my proposed change makes slings too powerful for high-strength characters I understand completely; I am merely suggesting some players like me might be confused over when a sling is considered a thrown weapon and when it is not, especially regarding which feats affect them. Hopefully this post helps to clarify their current behavior regarding Brutal Throw.