- Ok, a very small wall. Don't see the issue.

Indestructible Wall whose square area is one 5' square. Absolute, on-demand unbreakable cover. Free bridge or stepping stone. Interpose it between yourself and your opponent before walking away - they cannot follow, they must move 5' around, meaning they can't charge after you. Need to block a doorway? You have.

Freely available access to indestructible forcefields generated by level 5 spells is not appropriate for a level 1 manoeuvre.

- No issue here, if they are 30 feet away, in combat, and aren't just charging for a full attack they do need an option.

See Bruiser. You've now pretty much replaced their entire class feature with one manoeuvre. Also, why do they need yet another option when they're intentionally not fighting in melee? They could "use a bow", not "deal Greatsword + Str + Cha damage at 30'"

- 3.5 bonus damage. Not a big deal.

If you invest in Autohypnosios (not a bad thing to have), you have a 1D8 version instead.

Actual level of a stance that deals 1D6 of Fire damage to melee attacks for no disadvantage?
Level 6.

Mental Might, however, also works on ranged attacks.

I do not consider your idea of balance to be the same as my idea of balance.

- Fairly strong. But reach is just a feat away, anyway.

Yes, Reach is just a feat that gives you -1 to hit in melee as well away. Or this stance. At no drawbacks.

- +4 to AC verus an attack? Give me Wall of Blades any day.

If you're a brawler wearing a Chain Shirt, with an 18 Wisdom and only 10 Dex, you have 22 base AC. 26 with Adamant Will. You may use Adamant Will when flat footed.

Wall of Blades requires a roll, 1D20 + 6 BAB + Str or Dex Mod (let's assume +4). Mathematically, with no enhancements either way, you must roll a 12 to match the value of Adamant Blade.

- Not quite. Not really even close to as powerful as that sounds.

Actually it is. Pretty much exactly. Level 6 Soulknife can have a +1/+1 blade.

Fear: +2 to damage. Optional +10 bonus to intimidate checks.
Joy: +1 to all checks made with the blade.
Love: DC 12 + Wis to charm on hit for 2 PP? Nice actually, Charm Person is a level 1 spell, doing it as a side-effect to non-lethal isn't bad at all.
Sorrow: Ignore Morale bonuses - this basically means Inspire Competence, and can easily account for a +2 AC against a Poet/party. Optional Shaken on a DC 12 + Wis for the full encounter.
Wrath: +4 to confirm, power point fuelled Keen.

All of them count as +1 magic weapons. And may as well make it a Spiked Chain because you can make it anything you like.

These bonii? Forgettable, occasionally useful. The fact you have a +1 Enhancement weapon *on demand*? Yes, it really is that good. If you really want, get that Mental Might stance and you have your Psychokinetic enhancement bonus just like a real Soulknife.

You're welcome to disagree with me that it is imbalanced to have free access to a magic weapon at level 3 that cannot be found when you're searched, cannot be taken away from you, and reappears at no action cost if you're disarmed or it's sundered - For a feat for any class.

- +4 to int, that sounds like a feat.

A feat you get for free. That stacks with the actual feat. That you have no real penalty to having readied. So +8 total to initiative?

- But not this. That last one does sound OP.

Oh yeah, I just spotted this little gem: (Non-Swordsage adepts of the Sleeping Goddess discipline substitute their highest mental ability score for their Wisdom score when determining maneuver DCs)

So.... yeah, may as well go Intelligence for all those things.

However, the Brawler is much more likely to have a lower strength, and so hit less. Add in medium BAB and while not being at monk levels of suck, a brawler will hit far less often.
Challenge accepted.

Brawler with 16 Strength.

You're at a net -3 to hit against an 18 Strength Gladiator's first attack. Since you're flurrying, you're actually more likely to hit with attack #2 than you are attack #1.

Slap on an Enhancement of +2 and Weapon Focus for both.

+10/+10 vs +13/+7

Mithral Full Plate + 2, +2 Dex: 22 AC.
+2 Tower Shield: 28 AC.

Brawler has a 15% chance to hit, each hit.
72.5% chance to miss both.
Gladiator has a 30% chance to hit, and a 5% chance to hit.
66.5% chance to miss both.

A 6% chance against one of the best armoured targets you can hope to face is not "far less often".

In return, the Brawler gets a free undisarmable weapon, a better AC, Evasion, a better Ref save (at least), and frankly insurmountable SR on demand coupled with a decent self-heal is a whole lot better than anything else the Gladiator can come up with. I contend they would still be a very valid class.

If they're rebalanced in another way, that's fine, but they do need to be rebalanced.

The engineer is versatile in that he can be a healer one day, a bomber another, or a tank on one, but has trouble adapting to short-term problems.
I believe I may be in the minority here, but I honestly believe the invention part of the Engineer is distracting people from all the other things they can actually do rather well thank you.

Human Cannoneer

9 Strength
16 Dexterity
14 Constitution
17 > 18 Intelligence
10 Wisdom
8 Charisma

+4 BAB.
88 skillpoints.

Maxed Appraise, Craft (Alchemy), Craft (Weaponsmithing), Disable Device, Forgery, Listen, Open Lock, Search & Spot.
5 ranks in Knowledge (Architecture and Engineering), 1 skill trick: Clever Improviser.

Inventions, Smithing and Explosives only - 3/2/1

Smoke Grenade, Serum Injector, Crackerjack Caltrops
Climbing Spurs, Blunderbuss (Why does this have a crit range if it's a cone by the way? Should this be Reflex /2?)
Pocket Bombard

Extra Invention: Shrapnel Mine.

Feats: Grenadier (+1 to hit and damage with Splash Weapons), Mad Alchemist, Skill Focus (Craft {Alchemy}).
Gear of note: +2 Heavy Crossbow (If available musket instead, for the 1D12 damage die, reloading is irrelevant), Mithral Breastplate, Alchemist's Lab, and a whole slew of alchemical items.

Out of combat, he's in the role of the party trap handler, with decent scores in detection skills, artifice, appraisal (taking 10 reveals info about uncommon items), forgery and of course, the skills to make Alchemical items.

In his downtime, he makes things with Craft (Alchemy) like Auran Masks (Portable Waterbreathing/anti-toxin masks), Weapon Capsules (single use 1D6 Fire/Cold/Electricity damage or temporary ghost touch/silvered melee weapons - he makes these for his party mates), Screaming Flasks (1D8 Sonic plus deafness for 1 minute), Freeze and Razor Ice Powder, and of course, Alchemist's Fire, Tanglefoot Bags and Thunderstones, with a few Antitoxins just in case.

He can take 10 on Craft Alchemy checks for a result of 27, and make Craft (Poison) checks using his Craft Alchemy roll at -4 (I'll leave poison optimisation up to someone else). This is more than enough to make a DC 25 item every day, and harder items with a few buddies helping him (though a +5 competence bonus set of tools is apparently 2,500 GP or so and should cover most of it).

In combat, he can make a 5' square of difficult terrain as a standard action. If he hits a target with Alchemist's Fire, he can then use his Heavy Crossbow to deal fire damage for fire damage, dealing an additional 1D6 of damage, and setting them on fire for an extra 1D6 next turn, even if they doused themselves before getting hit.
Against mages, he can ready actions to throw thunderstones, disrupting their spell with a contested Concentration/Craft(Alchemy) check, in addition to being hit by a Thunderstone.

If he gets short on cash, he can sell these things at half their listed price for 12.5 GP profit a day thanks to only paying 25% on crafting items.

He can splash his waterskin across the floor and make slippery traps with Freeze powder, cover the square between him and his enemies with 1D4 + 1D6 hard to see Razor Ice. Since you can craft Traps with alchemical items incorporated, given prep time he can potentially set up traps with multiple Screaming Flasks and Thunder Stones activating in unison, then ready actions to set off this sonic deathzone whenever someone moves into range.

If he's feeling saucy, he can try to deny a lightly armoured mage his standard action by an aimed shot, using a smoke bomb to conceal and retreat if things don't go his way. He can stop a rampaging monster from charging him (well, by the current text it can actually charge, but not move - maybe this could be "does not get a move action next turn" as in Staggered or something? It's really hard finding wording for this).

He can climb anything with a DC 15 check or worse by taking 10, has a ranged touch attack at 5D8 damage, can make indefinite 2D8 cone attacks of Fire, Cold or Electrical damage with his Blunderbuss, or 1D10 damage of the same with his Heavy Crossbow.

Later, he can probably pick up Rapid Shot for the Blunderbuss with the rules as written, and if that gives him trouble, a Heavy Repeating Crossbow is only an EWP feat away for two shots a round full attacks with a swift reload.

So he's a full time trapfinder, lockpicker, who can appraise most things he picks up.
He makes valuable and useful items for the group, can basically pull off a level 3 spell non-magically for about 12.5 gp per person, has anti-caster functionality, has decent ranged attack options (and a lot of ways to avoid people getting near him), and has full access to a series of ranged splash weapons and a decent number of utility tools with a lot of different uses.
His toys include smoke bombs, making difficult terrain, booby traps, nausea causing gas attacks, clean, everlasting light supplies, water on demand, weightless sustenance as required, skill bonuses to a wide array of skills, curing of wounds, alleviating lost ability damage and lethal chemical attacks.

And then he has inventions as well.

Still think the Engineer isn't versatile?