While I do like me some melee tanks and unstoppable beasts, this guy needs work.

Right off the bat, he has no active abilities. Well, he has one. And it comes online once per week (and it might as well be a passive, since you're almost always going to use it when you die). So without a second of hesitation, I proclaim this class boring. In combat, the gladiator's job will be "I hit it with my sword." Out of combat, he suffers the Fighter Complex.

So you NEED revision, if you want this class to be halfway interesting. Tanking abilities, interrupts, attack boosts, aura buffs, whatever. There just needs to be something.

Moving on to the class features themselves...
Blood of Iron: +AC, cool beans. However, this is AC that applies to both flat-footed attacks and touch attacks and stacks with everything. For AC equal to your level, that's definitely a bit much. I'd make it a natural armor bonus.

Improved Unarmed Strike: Why?

An Ally is a Weapon: Sounds good. Generally, meleers don't pick one opponent, surround it, and then move on, so this is pretty situational for a moderate benefit. If the rest of the class were based around this ability, it'd be cool, but this really doesn't add anything to the quality of the class.

Uncanny Dodge: You generally just say "Barbarian" instead of "Barbarian or Rogue". I got what you meant, though.

Never give in: Why not just call this "Diehard", the way you called the bonus feat Improved Unarmed Strike "Improved Unarmed Strike"? It's not necessary, but continuity in your work is a nice thing to have.

Glory in Battle: This NEEDS revision. Not only can it make your party a walking RNG-smashers in every respect (including skill checks, wish for Pazuzu much?), but it falls prey to the Bag of Rats problem, where stabbing a rat gives you a +1 to everything, so you buy a bunch of them and then just spend an hour every morning stabbing them down to -1 HP and healing them back up.

Blood thirst: A heal based on you dealing the finishing blow to an opponent (fairly often) that heals you for 1d6 is a waste of space. This is level 6, where having +2 Con will get you 41 hit points. Healing an average of 3.5 means nothing in combat. Of course, outside of combat, the Bag of Rats problem raises its ugly head once more.

Evasion: At level 7? This is pretty weak for a level 7 class feature. I'd prefer a new level of maneuvers.

Death is glory: So you get an ability that can be activated by you not dying, called Death is Glory. There's a flavor disconnect here. Also, "combat rolls" is not a defined term--you need to set the parameters, or else people will try and make craft checks while claiming to fight dust mites over the course of months for the +2. In other news, this is a very weak ability and doesn't deserve to be at level 8.

Imp. Uncanny Dodge: All right.

Flesh of Steel: Personally, I'd prefer a chance to not get hit at all (+11 AC) over a reduction of damage at high RNG values. Set this to 1/2 level or 2+1/2 level, and it'll be OK.

Death is a choice of the weak: All right, sounds fine to me. But you need a better limiter than "1/week", because that encourages adventuring until the Gladiator uses up his auto-save, then resting for 7 days. Wash, rinse, repeat. If you perhaps make it a percentage chance (a level check, maybe?) or turn it into a contingent buff, where he can cast it as a swift action 1/day to ignore any killing effects. That would make players think twice when they want to use the ability, and prevent the spamming that you seem to be worried about.

Blood hunger: Again, with the low ConMod of +2, you have 72 HP at this point. 9 HP is nothing in combat. Also, Bag of Rats.

Never Give Up: Did I just hear the Bloodclaw Talons screaming for joy? This ability is far too easy to abuse. Make it a capstone, or toss it.

Soul of the immortals: Just say that the gladiator becomes immune to [Death] effects. Along with that, negative level immunity would be nice too.

Call to battle: First off, the DC for this will probably suck. As a gladiator, you want Strength and Constitution; maybe a bit of Dex for your AC and Int for your skills. Wisdom is also a big deal, for your will saves. Of all your abilities, Charisma is the most likely to be a dump stat, and that means your DC will be very low. In addition, "fight" needs to be defined. A beguiler "fights" by staying out of sight and reach while tossing down mind control effects. A dragon "fights" by flying out of reach, and strafing with a breath weapon and spells.

Gladiator's Prayer: Honestly, this is level 17. Limited wish won't break the game if you get it once per day, and 1/week class abilities aren't any fun anyways. Prince Zahn is overestimating its power at this level of gameplay.

Blood lust: Have I mentioned that this isn't nearly enough HP? Or the Bag of Rats?

Victor of countless battles: You need a DC for this. Please don't base it on Charisma.

On the lovely Tier system, this thing is probably 4-5. It's a padded sumo damage-wise, but can't fight abilities that force saves very well (especially Will). It also has weak damage, poor regeneration (outside of the Bag of Rats), and no flexibility. Definitely in need of work.