So, I'm working with a Human or Elf 25 point buy Aegis starting at level 8. Character died, campaign is limited on races so I have Human, Elf, Half Elf, Gnome, Halfing to work with. Path of War/Psionics is the only 3rd party stuff allowed.
I was working with trying to fit Combat Reflexes and TWF in with the Aegis, but it is hard to do that since an Aegis needs Str, Con, and Int. The other problem is, without a hugely high Dex, Augmented Expansion will eventually reduce Dex, reducing the usefulness of Combat Reflexes.
This leads to the idea of Weapon Finesse and Deadly Agility that work with TWF with Elvan Curved Blades. Augmented Expansion would still hurt some, but starting with 20 Dex and focusing only on Dex would help a lot more, but I'd lose out on some damage with not getting 1.5x bonus on damage when wield at 2H weapon, but as a Aegis most of your damage comes from the huge damage dies anyways.
Your options, as I see them:
1.) Don't take the size increasing Customization, problem solved.
2.) Use Prodigious Two-Weapon Fighting (PoW:E, use Str for TWFing prereqs) or Artful Dodger (Paizo published, use Int for TWfing prereqs, and counts as Dodge for feats) instead of Finesse/Agility.
I like Artful Dodge. Prodigious Two Weapon Fighting would be awesome if I wasn't fighting with 2 handed weapons.
That still leaves combat reflexes. Is there another version of it that isn't based off of Dex?
Not unless you're a Warder.
What, exactly, makes the Eleven Curve Blade so appealing to you? Since you're probably already buying Exotic proficiency, why aren't you using a pair of Falcata, or Bastard Sword, or the Estoc instead? All of which are 1H weapons that are all around roughly equal or better (the Estoc in particular is superior to the Curve Blade in every way).
Since if you take Prodigous TWFing, you don't need the "Has to be Dex based" bit.
And if you are still going Dex, you can save a hell of a lot of Customization points on the extra arms thing (making what you're doing possible from level 1) with the Estoc.
You're trying to split stats where you don't need to, is what I'm saying. pick either Dex, or Str. Roll with that. If you go Str, take Prodigious TWFing. If not, don't take Expansion. That extra 1 damage isn't worth the loss of to-hit and AC, and you can get Reach in other ways.
Ioun Stone for Weapon Proficiency. The Elven Curved Blade is Weapon Finesse-able weapon, making it the only 2H weapon to do so. With the Aegis having so many sizes up, I was thinking a Keen 18-20/x2 would be better off to maximize the damage from the massive damage die. At level 8, I'd have a weapon dealing 4d8 that is only going up when I actually get expansion.
Also Aegis gets two sizes up and Reach, meaning they can threaten a 20ft range. A 20ft Reach begs for Combat Reflexes, but without good Dex, Combat Reflexes with a waste.
Anyways, that was my though process. I'll like just go Str, dip into Warder since I didn't realize it was a level 1 class feature.
The Estoc is a 1H weapon that is Finessable, deals 2d4 damage, and has an 18-20/x2 crit rate. Pretty solid.
It being 2H is a hindrance to you, since you can't get 1.5x Dex to damage unless you're an UnRogue.
The damage die also wouldn't be as much of a help to you as a Dex user as you might think. With the Curve Blade, you're starting at d10. Assuming you go Huge (which I don't recommend for other reasons, but that's beside our point here), you're up to 3d8 damage. A change of, on average, 8 damage (5.5 vs 13.5).
You're also losing 2 damage from the 4 Dex lost, so down to only a 6 point difference, and you're losing 4 to-hit. That 4 to-hit is a BIG DEAL, since hit bonuses are a hell of a lot harder to get than damage bonuses. So going by the standard formula of -1 attack = +2 damage in terms of value, you're losing 8 damage on that trade as well.
Unless you're hitting all your opponents on a 1 even with the -4, it will lower your DPR by a good chunk I imagine, though I don't have all the info needed to run the full formula.
Imagine instead you had taken Augmented Weapon, giving you a respectable 2d8 instead, but with no loss of to-hit or damage from stats. That's a larger effective increase than going Huge sized.
Now, this does not take into account Reach, which is the main benefit of getting that big, but the damage is basically meaningless, it's a trap.
Now, instead, if you were to use a Falchion and get that 2d4/18-20/x2 with Str going instead of Dex, you're in bashville.
At the end of the day, I have at least 6 size increases. One from augment weapon, one from powerful build, two from elementail Flux stance, two from expandion. GM had ruled that the augmented weapon or whatever that says it doesn't stack actually does.
A 2d4 weapon goes to 12d6with 6 size ups.
A 1d10 weapon goes to 12d8.
U am going str since there are too many negatives to a dex build.
If you're ignoring both the RAW and FAQ that rules size increases don't stack, then sure. Major houserules like that should probably be mentioned up front, since it drastically changes the advice that can be given.
There is only one thing with the Aegis that as it doesn't stack, unless I am missing something.
Expansion augmented gives you two actual size increases.
Powerful Build increases weapon die and cmb/cmd, no actual size increases.
Augmented weapon increases weapon damage die but does not stack with any increased sizes (only GM ruling that has changed).
Elemental Flux stance earth makes your weapon deal damage as if it were one (and eventually two) sizes larger.
This is 6 effective size increases for damage doe, buy only two actual size increases.
There is only one thing with the Aegis that as it doesn't stack, unless I am missing something.
Expansion augmented gives you two actual size increases.
Powerful Build increases weapon die and cmb/cmd, no actual size increases.
Augmented weapon increases weapon damage die but does not stack with any increased sizes (only GM ruling that has changed).
Elemental Flux stance earth makes your weapon deal damage as if it were one (and eventually two) sizes larger.This is 6 effective size increases for damage doe, buy only two actual size increases.
If I am remembering the FAQ correctly only the largest of any increase takes effect.
Expansion, powerful build should be fine (actual increases, medium creature with a large weapon becomes large creature with a huge weapon - expansion states the increase occurs to gear etc). If you lose powerful build you are stuck with a big weapon though, which could be annoying. Effective increases like the augmented weapon and the stance would not stack. That would mean the feat and the stance are redundant (until the stance starts to give 2 bumps), they do the same thing, make the weapon 'effectively' larger.
Best case scenario you get 5 increases at 15th level Aegis (first opportunity to take the second Increased Size customization). At level 8 you have 2 from Powerful Build and the Elemental stance. You get access to the first size customization at 9 (so 3) and the stance will grant it's second increase at IL 10 (4 total).
You could get access to Expansion as a power through the power stone repository and the casting customizations BUT then you need to carry around a handful of power stones with Expansion in them incase you want to swap customizations or some how get screwed over and have to redo your choices. The earliest that happens is 11 (ML needs to be 7 for the double expansion).