1) The Weapon Aptitude feat was partially implemented. It was trying to simulate Weapon Focus, Weapon Specialization, etc. for the aptitude weapon by adjusting the PC's AB and damage bonuses whenever a weapon was equipped or unequipped. I took a different approach: when a player chooses an aptitude weapon after sleeping, I check if they have the Weapon Focus feat for any weapon and, if so, add a property granting Weapon Focus for the aptitude weapon to their skin; ditto for Weapon Specialization, etc. Advantages to this approach are that it makes checking for weapon equip/unequip unnecessary, and it allows me to apply the Weapon Aptitude feat to feats that would otherwise be difficult to simulate accurately (e.g. Improved Critical with an already Keen weapon). The only disadvantage I can see is that you end up with more feats than you should (e.g. you end up with Weapon Focus in both the aptitude weapon and the weapon you originally chose it for, since there's no way to remove the original feat), but the old approach had the same problem. My question: this approach makes it possible to apply Weapon Aptitude to feats the old implementation didn't attempt: Overwhelming Critical, Devastating Critical, and, I think, Weapon of Choice. Should it?

2) Battle Ardor is supposed to add the INT bonus to the critical threat confirmation roll. Is this possible in NWN1? I know NWN2 has Power Critical, which adds a constant +4 to the threat confirmation roll, but as far as I can tell NWN1 has nothing similar, so I'm thinking it won't be possible. If not, what would be a reasonable substitute?

3) Battle Cunning is supposed to add the INT bonus to damage against flatfooted foes. I haven't thought about this much yet, but does anyone have suggestions how to go about it? Or, if it's not possible, a substitute?

4) Battle Skill is supposed to add the INT bonus to the checks to Trip, Disarm, Overrun, or Bullrush. I'm assuming in NWN Trip/Overrun/Bullrush all translate into Knockdown, and Disarm is Disarm, of course. If there's no easy way to change the check for this (I haven't really looked into this yet), maybe the Battle Skill feat could just be turned into the Improved Knockdown and/or Improved Disarm?

5) Warblade is supposed to qualify for Weapon Specialization (and other fighter specific feats, if any) two levels later than a Fighter would qualify for them. How would this be implemented?

6) I notice in cls_feat_warbld.2da that a lot of feats have GrantedOnLevel set to 99, some others others to -1. I think I've figured out that -1 indicates that the feat should be in the Warblade's Bonus Feat list, but what does 99 indicate?

Sorry for the long post; thanks for any help or suggestions.

I've actually been working on a conversion of the Tome of Battle for Neverwinter Nights 2 and finished Warblade class features some time ago.  Here's what I did, but take it with a grain of salt as some of the scripting functionality of NWN2 doesn't exist in NWN.

1.  Did it almost the exact same way as what you're describing, only I used an active feat with a daily recharge.  The script when activated checks the weapon that the player has equipped in their right hand and checks the player's current family of Weapon Focus, Specialization and so forth.  A lot of checks are made and all of the family of feats that the player previously had are switched to the weapon's family of feats as the old are removed.

2.  This one I did the hard way.  The really, really hard way.  I needed to rebuild the entire combat engine (attack and damage rolls, animation, sounds, the works) so that I could implement strikes correctly.  So, having my own version of the combat engine at hand made it simple to modify the crit confirm bonus for strikes, however not basic attacks.  Cursed hardcode.  

Anyway, the solution I came up with was to run a recursive function ( Or a function that calls itself, usually with a DelayCommand, many bardsongs in NWN2 follow this structure), from the feat that checks if the player is in combat.  If the player is in combat, every other round the script runs my attack roll routines.  On that attack roll I apply the Int mod to crit confirmation.  I only do it half the time because essentially I'm making a separate attack roll each round, which is like rolling twice to see if I get a critical hit.  Only if my attack roll confirms a critical hit does it apply damage, and that only for the crit itself, not the full amount for the attack.  Long story short, over time the damage averages out to an amount equal to directly adding to the critical confirmation modifier.

3.  Again, the magic of recursive scripts comes to the rescue.  If you're in combat (targeting them) and they are not, apply an attack bonus.

4.  There's also Feint, but I can't recall if you have that in NWN.  You do have Discipline though which is direct counter to many of these.  Set a skill reduction effect on the pertinent skills that can influence these rolls.  Knockdown and Disarm are much trickier because you cannot directly influence these rolls.  However, NWN treats them as feats, and those you can add and remove with scripting.  For these, I rebuilt the Knockdown and Disarm rules, adding in the Int mod when appropriate.  The thinking behind this is that if I can't directly influence the engine's rolls I can reproduce them, and then remove the feats for a round when my rolls indicate I should.  This script is also run every round of combat because we're influencing the probability that and opponent can use Knockdown or Disarm.  If it isn't there that round they can't use it.  It's complicated, but it does work to achieve the same result as if we were able to directly influence the engine's roll.

5.  For this I edited feat.2da so that that Weapon Specialization and the like requires a proficiency feat of the same name, then I added those proficiency feats to the fighter and warblade class feat 2das at the appropriate levels.  Incidentally, this makes it so that any class with the proficiency feat can take weapon specialization and the like, should you desire to add the proficiency feats to their class feat 2da.

Hope some of this helps out.