Since I left seven months ago, they fixed Swashbuckler and shurikens, and made blitz easy button.
gibbons did a good job rehashing an old idea I had, but after much thought and a lot of spreadsheeting, I believe the best thrower build now would be:
Spreadsheet: (Google Drive looks shit, download and open in Excel):
https://drive.google.com/file/d/0ByPzquwSBGvvSXhmaXRfSmJtWHc/view?usp=sharing12 Arty/6 Bard/2 Rogue (Halfling)
See the link for detailed damage calcs versus what is probably the next best thrower build, which would be the most updated Shuricannon/Lvl 20 Monk thrower. With everything but Bard Song buffs included (but leaving out some item based procs and SA damage since it's virtually the same between builds and not that much), this build is a strong 9% total damage per throw ahead of a 20 Monk Shuricannon. With Bard songs this build pulls very slightly more ahead.
Additionally, I liberally gave the Shuricannon 40% Doubleshot, and only 50% for the Bard build. The bard build gains 12% static Doubleshot over the Monk however (Cores + Dashing Scoundrel), and 30% Doubleshot Action boosts (9 or so of them in LD) which should reasonably add about 10% averaged full time Doubleshot. So, I tried to be
very fair in my estimates. Because I didn't do exact Dexterity accounting, (Monk gets 4 from Wind Stance, this build gets 4 from Tensers, enhancement Dex is roughly the same, etc), I just gave them both 60 Dex. Based on experience, this is a reasonable Dex assumption. It can go as high as the high 70's, but that takes Cookies, several pots, etc.
So not only does it do more damage (and arguably less resistible damage in the form of physical damage), but this build has a whole other aspect that makes it sort of amazing: instakills and CC. Fascinate and Coup De Grace add a certain "oh shit" option all my other thrower builds lacked. Not sure how important it is, but I'm excited to play with it and see.
The sheet has all of the info, but it's a lot and I don't want to repeat it all, so if you want to check my math or see for yourself, just donwload it.
Summary:
Feats: (Heroic)
Extend
PBS
Shuriken Prof
Shuriken Exp
Quickdraw
IPS
IC Ranged
(Artificer)
Precision
Precise Shot
Rapid Shot
(Epic)
Empower Heal
OC
lvl 26: Lasting Constipation, Pos Spell Power, or Holy Strike
27: Dodge, Epic Reflex, or Combat Archery
28: Doubleshot
Enhancements:
(37) Swashbuckler all the way to Tier 5, take dex, action boost, Dashing Scoundrel, Blow by Blow, Exploit Weakness, etc. All the goodies.
(11) Halfling all the way to Skillful Thrower for Dex to Damage with shurikens
(27) Harper for Dex, Know the Angles, Adept I-III, whatever you see fit.
(5) To play with. Probably take Arbelester, and maybe more dodge in Halfling. Up to you.
Stats: Start 20 Dex, and split the rest of the points between Con and Int, but I would stress Int for KtA. Level up's in Dex.
Some rationale:
*Arty 12 is for self cast, extended Tensers. BaB has a large effect on throwing speed, and the 4 extra dex are a nice perk. This build would lose about 11% thrown speed without it. Also, Arty gives 3 Feats, SP, and extended longer Displacement casts from GS items. Having more bard and some ranger could be nice, but feats are tight, and scrolling Tensers sucks. So, 12 Arty it is.
*You could also trade Dashing Scoundrel for Canoneer if you want and use a Rune Arm. Kind of a toss up between 10% Doubleshot and 6 damage vs. the 20 Damage of Glass Cannon.
*Throwing Speed Tests were done this week. I started doing 3 short ones and averaging, but then I just went to 40 throws (counting the animation sound) and using that instead. Should be accurate to within a few basis points.