Here again I start with a disclaimer. The book present the state of the art as of Aug 2007. There could be changes.
Unified progression of defense, BAB and saves. A 10th level character will have +5 of those (thus +0.5 / level). Even at 1st level classes can significantly alter the base value. Class abilities modify them further.
All classes will get some self-healing power (already known). Cleric enhance the self-healing capabilities of nearby allies.
Bigger spell will be rituals (raise the dead for example). Rituals are different from spells (as of how I do not know).
Summoning spells are removed along with alignment specific ones (at least for now).
You chose to fight with a two-handed weapon or a weapon+shield. Other abilities build on this choice. I hope this will be changed, how would two-weapon fighting figure to this?
Powers can be divided into assault, defense and control. Assault is best suited to two-handed weapons, and ephasize offense and damage. Defense is about higher AC and such things. Control hinder and constrain the enemy (IMHO trip for example).
Some stunt a better if carried out with a specific weapon. Hammer are perfect for stunning opponents, while great swords for cleave.
The role as a defendes admittedly means that you are to defend the wizard and allow the thief to flank. I'm not happy with that. The fighter should be the primary damage dealer, not the rogue or the wizard...
A fighter feat allows Dex to be added to AC even when wearing hvy armor.
Fighters can keep monsters focused on them, by having bonuses on opportunity attacks and by following enemies. They guard allies by "battlefield control".
An example of at will power is the defensive strike. If you hit, you get bonus to AC against this foe.
Per encounter: dance of steel (just the name is given)
Per day: great surge which is a powerfull attack combined with some healing of yourself.
Psi will appear sometime and it will be a different power source. They design arcane and divine magic so that psi can fit in. Power over mind will be the main (or a flagship) feature of psi, thus charms are going to be nerfed (the avoid too much overlap).
These classes are mentioned is 3-4 paragraphs, it is not a confirmation that they are going to be in the PHB, just that they were experimenting with them (for some, like the paladin, warlord and the ranger, we know that they are going to be in the PHB).
Paladin: Still have smite ability but there are more types of smites (different form of attacks). Paladins and fighters are both defenders, but paladins rely on divine powers. There are evil paladins.
Ranger: Nothing more that we already know. Some scoutish abilities focus on movement, good with a bow.
Sorcerer: Make it more distant from the wizard. They barely control their spells, but unleash enough energy every time that some remains around them. For example after a fireball, they are cloaked in fire which sears enemies nearby.
Swordmage: An arcane defender with magic shields and armor, flaming sword and some self-bluff abilities.
Warlord: A martial leader, with the ability to buff and control over battlefield positioning.
Barbarian: The ability to rage is the centerpiece ability of this class. There are different rages. There is a mention of a "lightning panther strike" that allow movement and multiple attack. Barbarians are more feral, and bite attack was mentioned
Druid: Their spellcasting takes second seat. The primary ability is wildshape, which they can do a lot more often, but only shapes they have picked (like spells). They have some nature related spell to canst when in humanoid form.
Bard: Gets it power from otherwordly patrons (?). Its powers focuses on illusions and confusions, so that enemies hinder themselves. They can also inspire their allies.
Monk: Still in the design stage, but it will be a mobile striker.
Sneak attack is easier. Apart from flanking, some spell and special abilities will also give combat advantage to rogues. Combat advantage is the name for the state when a rogue can sneak attack a foe. Immunity to sneak attack is nearly gone. Immunities are almost gone from 4th ed, replaced by damage threshold (something like DR).
Rogues have follow-up attack after successful attack (extra damage or penalties).
High powered abilities allow multiple attack and tactical movement.
Rogues are still skill monkey.
Skill level rises with level. Listen & Spot; Move silently & Hide; Open lock and Sleight of Hand is combined. Knowledge (Arcana), Spellcraft and Read Magic is combined to Arcane. Approximately the skill list is cut in half.
Some uses of a skill, like the avoidance of AoO by Tumble will be tied to feats or class abilities. Trapfinding is a feat (rogues have it by default), but others can have it too.
They make pacts with devils, feys, the starts, elemental powers. Their initial pact determines a large part of their powers. There are four types of it: Infernal, Fey, Vestige and Star.
Primary attack is eldritch blast and soul ruin.
You can transpose yourself and later others as well.
Invocation can summon.
Curses are an integral part of your power. Curses are associated with your pact. They are per encounter damage dealing / crippling powers. Cursed creatures are easier to damage with your blast or soul ruin. When a cursed creature is dropped to 0 hp, you gain a powerful follow up attack against nearby foes.
As for alignment, most creatures and PC will be unaligned.