I'm not sure why you wouldn't be able to apply feats like Weapon Focus: Scimitar to a scimitar you conjure with Shadow Weapon. It says you "create a weapon in the form of any melee weapon...", which means that it's a real physical weapon of that type. Unless someone wants to argue that a physical object in the form of a scimitar isn't wielded as a scimitar, which doesn't make sense. Even a Flame Blade is wielded as a weapon, and it's insubstantial flame with no strength modifier; a Shadow Weapon is a physical weapon of that type.
The only trick that immediately cones to mind with Shadow Weapon is using the bonus reach and reposition properties to throw enemies around tactically, mostly just out of full attack range.
Anyhow, a free magic weapon is a free magic weapon. Do anything with it, really.
Losing out on AWT options is a pain, but yeah, I don't see what problems there could be with weapon focus or weapon specialization. There's an AWT which allows you to use WF/WS with other weapons in the same weapon group which you can't make use of due to the exact phrasing, maybe that's what you're thinking of?
Anyway, most things that you could do with a fighter are things that you could do with a gloomblade fighter. You can specialise in a combat maneuver or in DPR. The option of geting a free reposition on any hit from 9th might actually make reposition worth a couple of feats (make sure you get tactical reposition if so). Variant multiclass (magus) might be good even if you can't use the level 11 ability, the weapons you create have an OK rather than a great bonus.
One quite unique option for a Fighter that would fit a more supernatural theme would be to go high STR/WIS, and get Shaitan Style and Shaitan Skin. Elemental Fist plus Shaitan Style adds major punch to one attack per round (which is great when you can't full attack), and Shaitan Skin grants a very strong Stagger effect if you have high WIS. You could even go deeper into "temple Fighter" with one level of Monk, picking up Flurry of Blows with a temple sword or 9-ring sword while wearing a WIS AC armor and using Combat Style Master to cross Shaitan Style with Crane Style defense. And/or throw-in Mantis Style and Cornugon Stun for Stunning Fist sword strikes. Anyhow, plenty of interesting options with Monk powers and Fighter feat-stacks.
The way I see it, there are six types of weapon for a vanilla Fighter: Melee w/o reach, melee w/ reach, TWF/double, thrown, bow, firearm. Let's look at each of them.
1) Melee w/o reach: Nothing special, you can create different or new weapons as a move action. Nice against sunder/disarm, grapples, or type-based DR. Creating weapons with Ghost Touch, Holy etc. when appropriate is also nice.
2) Melee w/ reach: Same as above, only you really profit from the 9th level ability. Creating a non-reach weapon when needed is also nice, especially with Gloomstorm.
3) This is where it gets interesting. Unlike the similar Mindblade Magus ability, Gloomblade does not say you only affect one end of a double weapon with the given enchantment.
4) Sadly, Gloomstorm has to few uses per day, and returning is not an allowed property. We can create some (max. 20ft range) throwable weapons when in need, but it's not a possible character focus. If you're OK with the limited range prior to 9th level, a switch hitter build might be doable, though.
5) Melee weapon only. :-(
6) Normally, firearms are obviously ranged weapons, but Sword Cane Pistol or Dagger Pistol might actually work. If your GM allows that, it's actually an interesting concept, as with Gloomstorm, you could simply drop and create a new weapon when you misfire. Axe Musket and Warhammer Axe are also possible for a lowish level character (no free action reload without 3 levels in Musket Master, though).
@BadBird: Elemental Fist has far too few uses per day.
A Monk1/Fighter picking up Shaitan Skin at 11 has 5/day uses, and there are ways to get more. It's not like you need to throw your acid stagger at every goon that comes along; it's a powerful stagger for when you really want something staggered.
Gloomstorm could be very useful for barraging a target with thrown spears on an otherwise melee-oriented spear build. Once per level per day you can full attack from range with your main weapon; and there's ways to consolidate attack to one ability score. Two-Handed Thrower and spears is a mean full attack.
A Monk1/Fighter picking up Shaitan Skin at 11 has 5/day uses, and there are ways to get more. It's not like you need to throw your acid stagger at every goon that comes along; it's a powerful stagger for when you really want something staggered.
Except the DC isn't that high because you can't focus much on Wis (secondary stat, and you need 15 con), and you need to invest three feats to get there. Plus that dip, of course.
Gloomstorm could be very useful for barraging a target with thrown spears on an otherwise melee-oriented spear build. Once per level per day you can full attack from range with your main weapon; and there's ways to consolidate attack to one ability score. Two-Handed Thrower and spears is a mean full attack.
That's roughly the switch hitter I was talking about. Put the money you save on weapon enchantments into a Lesser Mighty Belt of Hurling, and you're doing pretty fine.
Shaitan's base DC is a Reflex save equal to what a Sorcerer's highest level spell would have. With a decent split score and a good headband (Gloomblade is rolling in cash), it shouldn't be hard at all for a Fighter to stack decent WIS. Then use your stacked WIS for more, like Cornugon Stun + Mantis. Now you're a Fighter who can throw many strong DC shutdown attacks each day through weapon strikes - even two types at once. And your Will save is great too.
Another option with throwing/melee spears is Guided Hand, making all spear attacks use WIS. And there's Menhir Guardian Monk for spear flurry.
There's always the boring stuff like power attack/furious focus for use with most/all weapons. Since you won't be using heavy armor you might like to go for owl style & its successors; it fits the image of a shadow-wielder and stretches your skill points further.
Shaitan's base DC is a Reflex save equal to what a Sorcerer's highest level spell would have. With a decent split score and a good headband (Gloomblade is rolling in cash), it shouldn't be hard at all for a Fighter to stack decent WIS.
The question is whether "decent" is good enough to invest three feats (and enforcing the dip, or needing a forth feat) for five daily attempts at a 1-round staggered. Your dex and int also suffer.
Another option with throwing/melee spears is Guided Hand, making all spear attacks use WIS.
That's two feats and a -1BAB dip. How about Desna's Shooting Star for a switch hitter build? Brownie points if you introduce your character with "I'm a charismatic guy who is good at talking to other people, and I won't need any weapons from the loot", and have the other players guess your class!
And there's Menhir Guardian Monk for spear flurry.
If only that archetype were aviable for unMonk! q_q
There's always the boring stuff like power attack/furious focus for use with most/all weapons. Since you won't be using heavy armor you might like to go for owl style & its successors; it fits the image of a shadow-wielder and stretches your skill points further.
If you are not using heavy armor, you might as well build towards Trained Grace.
Start with a two-handed weapon at low level, then move towards a pair of Kukri at higher level.
Shaitan's base DC is a Reflex save equal to what a Sorcerer's highest level spell would have. With a decent split score and a good headband (Gloomblade is rolling in cash), it shouldn't be hard at all for a Fighter to stack decent WIS.The question is whether "decent" is good enough to invest three feats (and enforcing the dip, or needing a forth feat) for five daily attempts at a 1-round staggered. Your dex and int also suffer.
From my perspective, you seem very concerned about investing feats, dipping levels and losing fractional bonuses on a class that's extremely dip-friendly, has loads of feats as a class feature, and is rolling in fractional bonuses.
Split WIS and a decent item means Shaitan or Stunning Fist is maybe a couple points off of a focused casting stat, the base DC is equal to a full caster's top-level spell, and Shaitan gets to target Reflex. For a Fighter who's going to face a full attack next round or a dangerous spell, what's it worth to have a good shot at inflicting one round of stagger or stun?
Shooting Star is very efficient, and Fighter can do some other useful things with CHA. The downside there is that you're dealing with a light weapon, rather than a spear with a bigger die that you can hurl with two-handed thrower.
With some GM fiat I could see the Focused Weapon advanced weapon training being used for a starknife to bump up its damage, the GM just has to be willing to consider "Shadow Weapon" to be a weapon group.
Unfortunately it is not.
If it were, the gloomblade could use martial versatility to apply all of his bonuses to any weapon. That would be pretty substantial.