Free extra save at the beginning of your turn nicely counteracts any ill effects your slightly lower AC and defenses might cause.
Compared to the barbarian who is a striker, I think the warden feels balanced in being a defender. I can now see some of the design decissions behind the barbarian a little bit better. Compared to PHB fighter or paladin, the warden feels a bit strong, but compared to MP fighter or Swordmage, it feels reasonable. I see a bit of power creep, but not game breaking so far. The class still fits into its role, and does it well enough without making other classes feel obsolete.
I'm liking a dwarf warden. I think the extra hit points can go a long way, especially considering you can stack Toughness on top of the nice boost in hit points. A Dwarf Warden with 16 Con could easily start with 38 HP's. Strength of Stone will provide a nice stream of temporary hit points. And dwarves love to use their second wind every encounter, which gains some additional benefit from a class feature.