http://www.wizards.com/DnD/Article.aspx?x=dnd/4ll/20120430
This right here. The Fighter design goals.
[h=3]1. The Fighter Is the Best at . . . Fighting![/h] This might sound like an obvious point, but the fighter should be the best character in a fight. Other classes might have nifty tricks, powerful spells, and other abilities, but when it’s time to put down a monster without dying in the process, the fighter should be our best class. A magic sword might make you better in a fight, but a fighter of the same level is still strictly better. Perhaps a spell such as haste lets you attack more often, but the fighter is still either making more attacks or his or her attacks are more accurate or powerful.
From the basic rules, it looks as though the cleric is going to be a better fighter. With the leaked phb, the ranger and paladin can clearly outfight the fighter as long as they have spells. The barbarian can outfight him as long as he can rage. The wizard can simply end an encounter with the right spell. The Fighter's schtick is instead "Can outfight any class when they are absolutely deprived of their resources".
[h=3]2. The Fighter Draws on Training and Experience, not Magic[/h] Fighters master mundane tactics and weapon skills. They don’t need spells or some sort of external source of magical power to succeed. Fighters do stuff that is within the limits of mundane mortals. They don’t reverse gravity or shoot beams of energy.
Mission accomplished. This fighter is absolutely mundane in every way.
[h=3]3. The Fighter Exists in a World of Myth, Fantasy, and Legend[/h] Keeping in mind the point above, we also have to remember that while the fighter draws on mundane talent, we’re talking about mundane within the context of a mythical, fantasy setting. Beowulf slew Grendel by tearing his arm off. He later killed a dragon almost singlehandedly. Roland slew or gravely injured four hundred Saracens in a single battle. In the world of D&D, a skilled fighter is a one-person army. You can expect fighters to do fairly mundane things with weapons, but with such overwhelming skill that none can hope to stand against them.
There aren't any rules for tearing off arms, and an unarmed fighter is severely crippled since they'd be using such low damage dice and unaided by their fighting style. A level 8 fighter would be absolutely annihilated by the level 8 dragon in the starter set. A level 20 fighter would be easily taken out by a group of archers because of bounded accuracy. The skill, relying on multiple attacks that always do the same damage, aren't really overwhelming.
[h=3]4. The Fighter Is Versatile[/h] The fighter is skilled with all weapons. The best archer, jouster, and swordmaster in the realm are all fighters. A monk can match a fighter’s skill when it comes to unarmed combat, and rangers and paladins are near a fighter’s skill level, but the fighter is typically in a class by itself regardless of weapon.
Only...no. An extra attack at level 11 is really all the fighter has to set himself apart from the others. The others have 5th level spellcasting with a slew of swift action spells that have extremely powerful and versatile effects. The best archer is a ranger who casts Swift Quiver. The best Jouster is a Paladin who uses any of the wide number of Smite spells at the moment of impact. The best swordmaster might be a fighter...if it was an eldritch knight.
[h=3]5. The Fighter Is the Toughest Character[/h] The fighter gets the most hit points and is the most resilient character. A fighter’s skill extends to defense, allowing the class to wear the heaviest armor and use the best shields. The fighter’s many hit points and high AC renders many monsters’ attacks powerless.
The fighter has one good save and then strength. Indomitable is nigh worthless against effects targeting his weak save. The fighter can wear heavy armor but so can the Cleric. The fighter gets 1 extra hp per level compared to the vast majority of classes. That's not enough of a distinction to make "many monster's attacks powerless".
[h=3]6. A High-Level Fighter and a High-Level Wizard Are Equal[/h] Too often in D&D, the high-level fighter is the flunky to a high-level wizard. It’s all too easy for combinations of spells to make the wizard a far more potent enemy or character, especially if a wizard can unleash his or her spells in rapid succession. A wizard might annihilate a small army of orcs with a volley of fireballs and cones of cold. The fighter does the same sword blow by sword blow, taking down waves of orcs each round. Balancing the classes at high levels is perhaps the highest priority for the fighter, and attaining balance is something that we must do to make D&D fit in with fantasy, myth, and legend. Even if a wizard unleashes every spell at his or her disposal at a fighter, the fighter absorbs the punishment, throws off the effects, and keeps on fighting.
Waves of orcs. A high level fighter gets 3 attacks a round, 6 if he novas. Even at high level, each attack is going to do something like 2d6+5 damage, which is going to be enough to finish off an orc slightly more than half the time. Meanwhile, a level 5 wizard can reliably wipe them out with a fireball. Or any number of the other hundreds of spells they have access to.
The fighter does not have enough hp to absorb the wizard's punishment, Indomitable does not work at throwing off the effects, and many spells are going to simply take the fighter out of the fight with trivial ease. Quite simply, the fighter just stops getting class features at level 9 with Indomitable. The extra attacks don't keep up at all with the bloated hp of higher level monsters, meaning the fighter actually does less damage relative to encounters as they level up. Even a subclass like the Battle Master is going to get its 3 best maneuvers at level 3, and each new one they get access to are going to be the ones they really didn't want in the first place.
So yeah, I'd love to hear Mearls try to defend how Next lived up to these goals.