Larian Studios Forums Divinity - Original Sin Divinity Original Sin - Beta Suggestion: Fortify/Stand ground.

The flee perk seems like a good idea, something in the line of greatly improving dodge and/or defense while suffering attacks of opportunity, or simply a flat immunity to it (although in such a state it might seem a little too strong and would become a no brainer must have quickly, which in my sense is never that good).

The defensive stance should use up all remaining APs but provide a scaling defensive bonus up to a certain amount, 5 or 6 as you suggest seems reasonable, with perhaps the possibility of making the stance stronger with perks and or abilities (such as increased physical protection in Way of the Warrior, increased magical protection in Sourcery and increased dodge in Way of the Ranger).

Let's say 2% physical damage reduction, 2% dodge, 2% magical protection for each AP used in defensive stance up to 5 points (max 10% each). Then perks or abilities might buff physical protection, dodge or magic protection so that each AP used will grant 4/6/8% instead of two. This way you get to choose when to use or not use the stance as well as choose what kind of defensive bonuses the stance provides. So you might have a warrior whose defensive stance will grant +40% physical damage reduction, +10% dodge and +20% magic protection (for 5 APs) and say an archer with +10% phys. prot. +20% dodge and +40% magic prot. (provided they spent their ability points correctly).

You can max each stat on each character, so they all have up to 40% protection on everything, but that would come at the price of not saving APs each turn, and having to spend points for these defensive buffs rather than something else.

Diminishing returns on the stance points out an interesting aspect, as to how to make this option limited in time in order to avoid maxing constitution and speed so that you can use low/medium cost skills every turn and still benefit from 5 AP defensive stance. I'm not sure diminishing returns would solve that. Perhaps make defensive stance available only if the character only moves during the turn, so that if you start using skills or attack monsters, you can't defend during the same turn.