New class previews mean a new set of at-wills! Unfortunately, the Warden's are rather uninteresting:
Earth Shield Strike - It's like 3.5's Dodge all over again! Thorough meh, worse than Thundering Armor. I give it a C.
Strength of Stone - Pretty handy, equal to Recuperating Strike, minus the bonus for raging. B.
Thorn Strike - This one's kinda neat, although it's a shame it doesn't extend to three for reach weapons. For a defender, pulling is better than pushing, so I'd put it as better than Tide of Iron: B+
Weight of Earth - Worse than Grasping Claws, since it's not a melee basic. Slowed is a pretty good condition for a defender to give out, though. B-.