To me, the Avenger is kinda... odd. It certainly has a strong controller vibe to some of its encounters and daily powers, but something about it just doesn't feel very... Strikery. Pretty much all the powers deal with either teleporting to your opponent, teleporting other opponents away from you and your opponent, or in one case phasing you and your opponent out of reality to duke it out undisturbed (this is an encounter power btw). The Avenger's utilities usually either deal with you reducing damage to yourself, healing damage to yourself, or moving to a better position to give damage to the enemy. You usually do the latter through teleporting.
It also seems rather odd that all the Avenger powers deal really small amounts of damage. Heck, they have a level 27 encounter power that does 1[W]. And stuns until the end of the next turn and can be used on a charge, but I don't really see how that makes up for it. And then it all goes a bit funny at level 29 when you get Final Oath and can hit a foe for 9[W]. I can see that large damage dies that the Avenger is throwing about and his large change to hit with Oath of Emnity being the reason for this, but it still looks odd on paper.
Also, the Avenger looks to be the toughest Striker available. Forget the Barbarian, the Avenger is the tough brute of the PHB2. His AC is awesome, and an Avenger in Hide with Improved Armour of Faith can make a Dwarf clad in Plate seem open to attack. His extra hit points further enhance this toughness.
I'm going to have to try the Avenger out a bit before I can make a final verdict, but right now he looks to be somewhat behind the Rogue and Ranger in DPR (though he certainly looks to be far more tough). I'm really interested in what some other people may think.