Do Swashbuckler's Insightful Strike, Swordsage's Insightful Strike and Shadow Blade feat stack?

Question

3rd level of Complete Warrior's Swashbuckler class grants Insightful Strike:

...applies her Intelligence bonus (if any) as a bonus on damage rolls (in addition to any Strength bonus she may have) with any light weapon, as well as any other weapon that can be used with Weapon Finesse, such as a rapier, whip, or spiked chain....

4th level of Swordsage class from Tome of Battle grants Discipline Focus (insightful strike):

... you can add your Wisdom modifier as a bonus on damage rolls whenever you execute a strike from the chosen discipline...

There is also Shadow Blade feat from same book:

While you are in a Shadow Hand stance and attack with one of the discipline’s preferred weapons, you can add your Dexterity modifier as a bonus on melee damage for attacks made with the weapon.

Short sword is light weapon preferred by Shadow Hand discipline.

Build with 3 levels of Swashbuckler and 4 levels of Swordsage (specialized in Shadow Hand discipline) looks valid.

Does that mean that when executing Shadow Hand strike, armed with short sword, with Shadow Hand stance active, this character deals 1d6+STR+DEX+INT+WIS damage (not counting possible additional damage from strike)?

Answer 1

That is correct. None of the bonuses are typed, and they come from different sources, so they stack.

Ultimately, this is a very costly exercise: you have to improve four different ability scores, you need three levels of swashbuckler and four of swordsage, and a feat that locks you in to a Shadow Hand stance. And even then, it only works when you use strikes of the appropriate discipline, which means most of the time you’re not full-attacking and applying those damage bonuses multiple times. The levels of swordsage, of course, are quite good, and Shadow Hand stances are pretty solid, so that’s not all bad, but you’re still talking about a lot of effort. And the multiple ability dependency you’ve inflicted on yourself is quite burdensome.

In contrast, it’s possible to add Charisma to damage 2-4 times. Strength is added 1.5 times with no investment at all just from using a weapon in two hands, and there are ways to add it again. Power Attack doesn’t rely on ability scores at all, and can add twice one’s level to damage. Any of these is likely to result in much higher amounts of damage than are four separate ability scores being added to damage. And they have fewer restrictions, so for example they can just be used on a full-attack and applied to each of your iterative attacks instead of just once.

So, basically, this is a way to pump damage, but it’s fairly inefficient. Much better alternatives exist. Which says something about 3.5, no question, but ultimately the game pretty much is rocket tag.