However I am planning a similar build for my next playthrough to take advantage of the early +4 Two-bladed Sword Drops in Swordflight. But I wanted something more thematic for roleplaying. Tell me what you think...
The trouble here is that the reason I gave players early access to good double-sided weapons is because double-sided weapons are actually kind of a bad choice, so I was trying to make them a bit more viable for the benefit of players who wanted to use them just for the fun of it. Basically you have to take four feats (Exotic Proficiency and the three dual-wielding feats) so you can give up both the shield AC bonus and the extra two-handed STR bonus...and even if you are committed to doing all that dual-wielding kukris (better damage against everything not crit-immune, finessable if a DEX build and better chance of getting Devastating Criticals if a STR build) probably makes more sense.
But assuming we do want to try out dual weapons just for fun we can consider your build. Some thoughts on it:
Why are you starting with DEX 17? Since you plan to be a STR build, it seems those 2 ability points might be better spent increasing STR, or maybe even CHA. You only need DEX 15 to get Ambidexterity, and can probably max out light armor DEX AC with item bonuses + Cat's Grace spell/potion.
You have 15 BAB at Level 20. You really want to figure out a way to get another COT level in pre-epic, so you can get 16 BAB pre-Epic for 4 Attacks per Round. Dual-wielding is all about maximizing APR.
You are taking the Discipline skill, and apparently will only have 18 points in it at Lvl 30...any attack roll high enough to get through your AC in the first place is going to easily beat such low discipline, so it is probably not worth it. It might occasionally help you out on natural 20 hits accompanied by a Knockdown or such, and there are occasional scripted checks against Discipline in Swordflight, so a case could be made for it, but both of those are rare cases so probably you should spend those skill points on something else.
I am not sure Lingering Song is the best feat choice at lvl 21. If you eventually take Lasting Inspiration you will render Lingering Song mostly redundant. Also, as a rule, you want to try to take epic feats in epic levels,.
On that subject, it would also be good if you could find a way to take Improved Critical pre-epic, and if possible take Overwhelming and Devastating Critical at some point. Blindfight and Toughness are also very good feats to have if you can fit them in somewhere.
Considering several points above, possibly you want to take fewer Shadowdancer levels and more COT levels. The main reason one would take 10 Shadowdancer levels is to get Defensive Roll and Improved Evasion so as to qualify for Epic Dodge without Rogue levels, but as you are not a DEX build you cannot get Epic Dodge anyway, so you do not really need that many, though giving them up will cost you a few skill points.
A possibility to consider would be replacing COT with Ranger, since you intend in any case to be using light armor, so as to get the dual wielding feats free, as well as perhaps the Animal Empathy skill which has many uses in Swordflight. You also would need a lot less Dexterity that way as Rangers get the feats free and do not need a minimum dexterity (DEX is not doing that much for you here anyway, as, again, you can max out light armor AC w/items/Cat's Grace). The main downsides are that you would have to take at least nine levels to get Improved Two-weapon fighting, presumably at the expense of Shadowdancer levels (though you might want more warrior class levels for more BAB anyway), and that neither Ranger or Bard is a favored class for Elf so that would likely give you an XP penalty for that race. As you would not need much DEX with Ranger you could replace Elf with Human or Half-elf if you are just using Elf for the DEX bonus. If you want to play specifically as an Elf for some role-playing reason though you would need to keep Ranger and Bard levels in balance (resulting in fewer Bard levels ultimately).
After all the trouble you went through, you might be the first person ever to qualify Swordflight as "too easy."
age Armor's Dodge Bonus+Shadow Shield scrolls. With a Shield if I need the extra AC, I get 65. Then I can put on Curse song in the hardest fights to making them a lot easier, and then divine might to end fights even easier. Balor's? They can't hit and it's only a matter of time before they die.
