This has been discussed since 2.0 was released in the forums and Dev Tracker. New Gear (69 and 72) armor bonuses DO NOT stack with pre 2.0 gear (Dread Guard- Campaign - Columni - Tionese). The set bonuses in some cases/classes for lvl 55 gear are different than pre 2.0 lvl 50 gear so the bonuses cannot stack.
And even more dumb.
This game is great but this is plain dumb.