Something I noticed while reading the new Pathfinder PHB is that a few of the standard SRD classes haven't been updated. This kinda sucks, so I figure I'd take a stab at it.
Dwarven Defender
[spoiler]
Hit Die: d12
Requirements
Race: Dwarf
Alignment: Any lawful
BAB: +7
Feats: Combat Expertise, Endurance, Toughness
Dodge was kind of a weird feat, given this class doesn't move all that much. Expertise makes more sense. The other requirements were OK.
So this class still requires 2 non-Fighter bonus feats to even qualify? That was the biggest problem: two of the three feats couldn't be selected through Fighter levels alone. Also, level 7 is a Dead Level for many classes. Lower the BAB requirement to 6.
If anything, the class should require more defense-oriented feats, like Combat Reflexes (to make sure things trying to move past you take a beating for trying).
Class Skills: Craft (Int), Perception (Wis), Sense Motive (Wis)
Skill Points: 2 + Int
Crappy skill list, but with Pathfinder's rework of class skills it's not terrible.
What would you do if the DD has an Int score above 13? Kinda sucks when you don't have enough class skills worth mentioning. At least put Tumble in there, IIRC Pathfinder allows you to counter-tumble people.
AC Bonus: A Dwarven Defender gets a Dodge bonus to AC based on his level. See table for details. This bonus is lost whenever a Dwarven Defender would be denied his Dex bonus to AC.
Let me put this simply: +4 for the cost of 10 levels is too small. I can get +10 off of 2 levels of Swordsage. Untyped, always active, and works in light armor.
Change it to letting them use either their Con or Str to AC in place of Dex (and make sure it doesn't get capped by their Max Dex Modifier). Then you have a class feature worth taking.
Defensive Stance:
Even worse than the original, actually. The duration is nice, but the fact that he can't even move (the original at least let you take 5ft steps) means the trademark'ed call still applies:
"Look, a Dwarven Defender! Everyone, walk briskly!"
Let them move up to half their speed each round. Hell, full speed, they're Dwarves after all. It kinda sucks when your entire PrC is ruined by a wide-open field. Or a 40sqft room.
Defend Ally: Starting at 3rd level, a Dwarven Defender can grant an ally a +4 dodge bonus to AC. The ally must be adjacent to the Dwarven Defender, and only one ally may be affected at once.
At 6th level, 2 allies may be affected at once.
At 9th level, 3 allies may be affected at once.
Bonus is too small. Have it be the DD's Con modifier. Or have him act as mobile Soft Cover for his allies, but not his enemies.
Defensive Reflexes: Starting at 4th level, a Dwarven Defender improves his ability to attack targets that provoke him. He may make an additional attack of opportunity for every 2 levels of Dwarven Defender he posesses (for example, a Fighter 7/DD 4 without Combat Reflexes could make 3 opportunity attacks in a single round). This ability does not stack with Combat Reflexes; use the greater value.
Have it stack with Combat Expertise, and change the Endurance requirement to Combat Expertise. Not gonna break the game.
Damage Reduction: At level 5, a Dwarven Defender gains damage reduction 3/-. This improves to 6/- at level 10.
Not worth it. The values are too small. Enemies are dealing 40+ damage/attack at 17th level, when the DD would normally get the greater version. His HP isn't going to stand up to that. Have it be 10/Adamantine and 15/Adamantine. That's actually respectable DR.
Mobile Defense: At level 5, a Dwarven Defender may take a 5' step while in a defensive stance.
I should not have to spend 5 levels in a PrC to not suck when using that PrC's primary class feature.Improved Uncanny Dodge: At 6th level, a Dwarven Defender can no longer be flanked, except by a rogue 4 levels higher.
Defensive Block: At 8th level, any creature that provokes an AoO by moving through a Dwarven Defender's threatened space is subject to this ability. If the Defender hits with an AoO, the targeted creature must stop in the square it is currently occupying. If the creature has actions remaining, it may resume movement (though it may provoke additional AoOs based on position).
So its Stand Still, but worse?
Greater Mobile Defense: At 10th level, a Dwarven Defender may move up to his base speed while in a defensive stance. He cannot run or charge, nor make any other movement besides walking (jumping, tumbling, climbing, etc.). He may take the Withdraw action normally, if he chooses.
As above. This should be available from the start. The Deepstone Sentinel can end a Stone Dragon stance by taking a Move action, and then re-enter that same stance after moving at no penalty. You class has to Fatigue himself every time he does this, and can only maintain the stance for a few minutes/day (whereas the Sentinel can be in his stance effectively 24/7).
In all, your changes are minor, and actually worse in some places. It fails to address the primary problem the DD has until the 10th level, at which point the class becomes playable. You may not realize it, but only having a 20ft move speed actually does hurt a melee character. It turns a 60ft charge into a Move action and then Charge next round. Melee has a hard time keeping things inside its melee reach, and the DD can't do his job (tanking) if everyone just has to take 15ft extra movement to avoid ever even stepping into his melee reach.
Also, don't use Pathfinder melee characters. They're actually worse than the original, a fact that has been discussed in several other threads.