In general, there are no WotC plans to switch over D&D hp and AC to the SW vitality/wounds and defense bonus system. Many folk have discussed making this switch in their own campaigns, however.
For a conversion of D&D hit points to SW vitality/wounds points, go
here .
As for defense bonuses, I'd suggest the following progressions:
-Fighter, Paladin, Cleric, Sorcerer, Wizard: poor
-Barbarian, Druid, Bard: medium
-Monk, Ranger, Rogue: good
If you continue to use armor bonuses to AC, then allow the fighter and paladin to stack their defense bonus and armor bonus, as per the Soldier class in SW. The druid and bard get medium progression for balance reasons only (otherwise, they get hosed).
If you use armor as a damage soak: Well, you'll have to make up your own system or analogize from d20 games which use this rule. One simple rule is to convert the armor's AC bonus directly to DR; so a chain shirt would grant DR 4/-, while full plate +5 would grant DR 14/-. I don't know how you'd deal with the interplay between armor and defense bonus, though; maybe make the "max defense bonus" equal to the max dex bonus for each type of armor, and allow fighters and paladins to ignore the maximum.