STR (10) / DEX (16) / CON (8)
INT (10) /WIS (10) Cha (16)
Play to your strengths, pad up the weaknesses. A starting score of 16 Cha is far too high for a secondary ability score which you have no bonus to. Especially since you have one class feature that scales of charisma as far as I can tell.
You'd do much better to just dump Cha and buy light armor instead. Str 10 may also be too much, since you won't qualify for Power Attack anyway. Con is really important, so raise that to 14(-2).
STR (8) / DEX (18) / CON (12)
INT (12) /WIS (14) Cha (7)
In place of the Irrepressible social trait, take the Empathic Diplomat region trait so you use Wisdom for Diplomacy checks instead of Charisma.
-1 dmg
-1 to Diplomacy checks
+1 skill rank per level
+2 to Will saves
+2 to Fortitude saves
+2 Hp per level
+1 to AC, Attack, Initiative, Reflex, Etc
-3 AC (loss of Cha to AC)
Item changes:
Bracers of Armor (+2) -> +1 Mithral Chain Shirt, +1 Buckler
Net gain of +5 to AC, and some extra gold
AC total assuming you keep the dexterity belt:
Armor class (24) Flat (19) Touch (16)
Base(10)
Size(1)
Natural Armor(1)
Dex(4+1)
Armor(5)
Shield(2)
Dex builds are usually weaker than strength builds at lower levels, and in your case you've chosen an archetype that doesn't reward full-attacking like the normal class does. In addition, you're locked out of Power Attack thanks to your huge strength penalty and Piranha Strike won't normally apply to a one-handed weapon like the Katana (you need the Effortless Lace). So yes, your damage output is definitely on the weaker end.
To put things in perspective, you'd deal 11.5 average dmg per hit against a challenged foe (you forgot to add the Enhancement bonus). A level 1 raging two-handed barbarian would deal an average of 16 per hit without Power Attack.
LV(1) Quick Draw
LV(3) Improved Initiative
LV(5) Iron - Will
You're effectively given Quick Draw for free at level 3 with the Weapon Expertise class feature, so taking it as a feat is a waste. Improved Initiative is a good placeholder feat, but you should focus on damage at the moment. And Iron Will isn't as big a priority if you take the point buy I proposed.
LV(1) Piranha Strike
LV(3) Weapon Focus (Katana)
LV(5) Slashing Grace (Katana)
While Slashing Grace doesn't stack with Graceful Strike, there's a lot of levels left for the bonus to get equal. I'd grab it and then retrain at lv 12-14.
+1 Katana: +13 /1D6+6
Piranha Strike: (-2/+4)
Challenge: (+2/+5)
So an average of 18.5 against your challenged foe, which is a lot better than your previous amount. But if you're looking for damage I'd check out a TWF build, using a different archetype.
Standard Samurai is actually a pretty good class for it, since you get proficiency with both weapons and you'd add your Challenge bonus to all main and off-hand attacks. The Brawling Blademaster archetype would allow you to make a Strength or Dexterity-based TWF build, so any race would be good for it.
Basically any race that doesn't have a strength penalty would work fine, but these are the 13RP and below races that has a strength bonus:
Half-Elf, Half-Orc, Orc, Variant Tiefling, Variant Ifrit, Oread, Variant Dhampir.
A good order would be one that increases your attack bonus, since you're already behind with the -2 from TWF and also having to upgrade two weapons instead of simply one. So Order of the Dragon and Order of the Green are both pretty good.
1 Power Attack, IUS (B)
3 +1 Feat, TWF (B)
5 +1 Feat
6 Improved TWF (B)
7 Chain Challenge
9 +1 Feat
11 +1 Feat
12 Double Slice (B)
As you're talking about Crane Style, do you want to fight weapon-and-fist as the archetype is intended for? Since Crane Wing requires one hand free.
Alright, but Crane Style does mean that you'll be leaving the katana and wakizashi behind for katana-n-fist or wakizashi-n-fist. But that's probably a bonus since you'll then ignore the TWF penalty on attacks vs your challenged target (thanks to the Harmonious Flow class feature). But even with the bonus feats you get, it takes quite a long time before you reach Crane Riposte.
1 Power Attack, IUS (B)
3 Dodge, TWF (B)
5 Crane Style
6 Improved TWF (B)
7 Chain Challenge
9 Crane Wing
11 Crane Riposte
12 Double Slice (B)
Remember to buy Handwraps for your fist instead of an Amulet of Mighty Fists. The handwraps would cost the same to upgrade as a normal weapon, instead of double like the AoMF.
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Have you decided on a race?
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Edit:
On second thought, it's probably better to just take Greater TWF at lv 12 (or another combat feat) since Double Slice doesn't affect Power Attack anyway.
Blade's cool, but remember in PF that you need to have your healing nailed down to play a dhampir. As a samurai you won't be providing any of your own so make sure someone in the party can/will wave a wand of inflict light wounds around, or channel negative energy or something.
Haven't you had a fairly long discussion about the intimidating slayer? Anyway, TWF requires more feats, which makes 2H easier. The extra feat from being human is nice to have but certainly isn't required. The only real requirement is being medium-sized, small is a pain for intimidation.
Re dhampirs and healing, I meant that literally - talk to the other players and make sure that at least one will have a character willing and able to use a wand of inflict light wounds (or infernal healing assuming your GM hasn't put a significant price on devil blood) and you're OK to play a dhampir.
I'm a fan of catering to strengths and dumping the weaknesses even further (although a kobold with a starting strength of 3 would be, eh, perhaps a bit too much; we wouldn't want the poor fellow to collapse if we rest a feather on his head).Play to your strengths, pad up the weaknesses.STR (10) / DEX (16) / CON (8)
INT (10) /WIS (10) Cha (16)
A starting score of 16 Cha is far too high for a secondary ability score which you have no bonus to. Especially since you have one class feature that scales of charisma as far as I can tell. You'd do much better to just dump Cha and buy light armor instead. Str 10 may also be too much, since you won't qualify for Power Attack anyway. Con is really important, so raise that to 14(-2).
Agreed; I wouldn't spend on charisma here unless you're a cha-bumping race pursuing multiple avenues of attribute-exploitation (see build below which raids it three different ways).
Spending 5 build points to get strength from 6 back to 10 is just a horrible travesty in point-buy.
The main trouble with Warrior Poet here is that some of the class benefits are a poor fit to the massively-penalized kobold. For example, they're getting a lot less out of Graceful Strike than they could be; i.e., a human with a 14 STR (3 or 5 build points) is gaining +3 +(larger hit-die) extra damage using a finesse weapon in two hands compared to the strength 10 kobold. Otherwise, Warrior Poet is mainly an end-loaded class that doesn't really shine until mid-levels, and it sucks in the early game (e.g., Skirmisher’s Challenge is a straight downgrade from regular Challenge). The archetype has a lot of fiddly bits that do not appear to be particularly useful unless you're multiclassing, and have a good deal of system-mastery.
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Don't sweat your saves as a samurai; you should get a lot of mileage out of Resolve(Resolute) even with mediocre attributes (if you save it for will-saves, it's like getting a super-duper version of Improved Iron Will that you can use multiple times per day, and choose which of your die rolls you want to keep).
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Anyway, let's try to build a Str-penalized small-sized Warrior Poet samurai who isn't straight awful at low level. (I will of course shamelessly multiclass, because martials can have nice things....)
Halfling
STR- 10
DEX+ 17 (raise 4th)
CON: 14
INT: 12 (halfling, 15,15,14,12,12,8 20pt array)
WIS: 8
CHA+ 17 (raise 8th)
racial alternatives: Fleet of Foot
character traits: Dangerously Curious, Adopted (human: Wary of Danger)
01 barbarian1 [Savage Technologist][move+10], Extra Rage
* move40, and rage to Str14/Dex21 for 12 rounds/day.
02 samurai1 [Warrior Poet][Flourish:Exodus of Speed][Graceful Warrior]
* Pick up Resolve.
* Move50 (untyped) = Speedy Gonzales halfling outruns barded mounts!
* AC = 10 +1(small) +5(raging dex) +3(cha) +4(pre-combat UMD'd Mage Armor wand charge lasting one hour) = +23
03 monk1 (Kata Master[Panache]/Monk of the Iron Mountain)][Mobility], Additional Traits: Martial Manuscript (faith), Monk Weapon Skill (combat)
* A level of monk here brings a lot of benefits: 1) flurry with a waveblade and be +1 damage and +2 confirm crits with it; 2) saves shoot up even more (halfling Luck + monk level + rage buff means +6 to will saves and rolling twice via Resolve/Resolute -- so we can easily dump wisdom for more Int); 3) Kata Master's Panache puts charisma to use even more; 4) while Poet grants Spring Attacks sans prerequisites at 6th, we still want Mobility, and that feat is on the monk bonus feat list, so we take it here; 5) TWF is annoying because it eats a feat-slot and requires upgrading two weapons; so by flurrying instead we save a feat, and only need to upgrade one close/light weapon (the waveblade) and one Poet-specific weapon (katana or naginata).
* Buy an opalescent white pyramid ioun stone (cracked, keyed to waveblade) if GM invokes RAW regards restricting monk weapons to those listed in the CRB. At 1500gp it's not exactly cheap at 3rd, but as you're budgeting zero for armor, cloaks, and bracers, it's well worth it for the best light weapon in the game.
04 WaPoet2 [Order], DEX>18
* Order of the Warrior is arguably strongest, but Order of the Songbird is quite tempting for a high-charisma build (and the monk level as 2nd makes Perform a class skill), and gets better at higher level when you can buff the party as a swift-action (although it is a competence bonus, and your allies might already have inexpensive gear that overlaps the granted bonuses).
05 WaPoet3 [Flourish:Exodus of Speed]], Risky Striker
* move60 now
* +4 damage available with with melee weapon without sacrificing attack-bonus
06 WaPoet4 [Graceful Strike]
* weapon damage bonus to katana or naginata: (STRx1.5) + (WaPoet/2)
* weapon damage bonus to waveblade: (+1 trait) + (DEX, when Agile)
07 WaPoet5 [Flourish:Uncanny Guidance], Piranha Strike
* up to +8 melee damage with light weapons (get Effortless Lace for the katana, so it and the waveblade are both light)
08 WaPoet6 [Battle Dance:Spring Attack], CHA>18
* Figuring a move of 70 with one-hour Longstrider wand charge, you're built to acrobatics in, drop a big katana bomb, then dart back out of reach. If crowded, you shrug and switch to flurrying and unload three attacks with a Furious/Agile waveblade.