The 3rd level Tome of Battle Maneuver Insightful Strike and it’s 6th level equivalent, Greater Insightful Strike are a little unusual in that they inflict damage equal to your concentration skill check.
A character that maxes out his concentration skill will find this maneuver useful. The only problem is what happens in the event of a critical hit? Opinion is divided among gamers as to which interpretation is correct. There are those who believe the damage should be multiplied on a critical hit and those who disagree.
The Sage from the Wizards of the Coast sides with the former group.
Let us consider for a moment the 6th level maneuver, Greater Insightful Strike. As a level 11 Swordsage or Warblade, the highest concentration score you can achieve is 14 plus bonuses from feat, constitution and magic items. A character with the skill focus (concentration) feat and 14 constitution, wearing a Tunic of Steady Spellcasting +5 and a +4 Amulet of Health should have a concentration score of 26. Obviously, this is the ideal scenario, but even without all the neat bonuses from the magic items, it should still be around 19 with the feat and constitution bonus.
On top of this, a concentration skill check is made by rolling a d20 and adding your concentration score. If this represents the damage you can inflict using this maneuver, you can imagine how powerful the maneuver can be.
Bearing all that in mind:
- A level 11 fighter with a strength of 20 (starting strength at level 1, 18) and weapon specialisation wearing a Belt of Giant Strength +4 will do, on average, 21 points of damage with a +2 Greatsword. 42 on a critical hit.
- The average damage from Greater Insightful Strike is 72 ((roll 10 on d20 + 26) x 2) – regardless of what weapon you use.
- Without magic item bonuses to concentration, the average damage is 58
- A character will critical hit 30% of the time with Greater Insightful Strike using the improved critical feat with a kukri, doing 144 damage (116 without item bonuses to concentration).
- Weapons with high critical multipliers such as handaxes will do 216 points of damage (174 without item bonuses to concentration) on a critical hit.
- A light pick can do as much as 288 points of damage (232 without concentration bonuses from items)!!! That’s enough to kill most demons in one attack… and grievously wound the Balor!
- The initiation action for Greater Insightful Strike is only a standard action.
I used light weapons with high critical threat ranges or multipliers just to demonstrate the absurdity of allowing critical hits for (Greater) Insightful Strike.
If you compare the Insightful Strike tree with other maneuvers of the same level, you should be able to see the imbalance:
Rabid Bear Strike – another 6th level maneuver which can be compared to Greater Insightful Strike in terms of it being a pure HP damage based maneuver – does an extra 10d6 damage (35 on average) which is not multiplied on a critical hit. While highly improbable, a Warblade scoring a critical hit with a greataxe while using Rabid Bear Strike and rolling maximum on all his die rolls would do around 144 damage. This is the same average damage on a critical using Greater Insightful Strike, even when using a dagger.
It’s true that some opponents are immune to critical hits, but magic items can render this immunity irrelevant (see the Magic Item Compendium) and the damage output of the maneuver would still be very high, critical hit or not.
Considering that Greater Insightful Strike can potentially be more powerful than some high level maneuvers if you allow the damage to be multiplied on a critical hit, I think a case can be made to disallow critical hits using Greater Insightful Strike.
And to quote the maneuver description:
As part of this maneuver, make a melee attack. If this attack hits, you do not deal normal damage. Instead, you make a Concentration check and deal damage equal to the check result.
Let me put it another way, it is a form of damage that does not follow the usual rules of the game. And this includes critical hits.
If you’re still not convinced, the Tome of Battle has already been derided by some for being overpowered. Allowing critical hits for Greater Insightful Strike will only make it worse :-).