Shades do the exact same debuff as Deep Slash/Herioc Slash does, they no longer stack in 1.6 so it's either or. I agree 100% on the Defensive Stance morph (I personally use Absorb Magic). I also use Refreshing Path to keep up Major Ward so that I'm Armor hard capped 100% during fights and since RP has a 11.5 second duration and with 7/7 Heavy Armor NB's get Major Ward for 11 seconds it's a great fit.you also need inner beast, deep slash, one of the defenstive stance morph, he has the morph of soul strife that increases health restoration.
I would switch dark shades with a defensive stance morph (the one you prefer) for the passive bonus.
Then on my off bar have again , structure enthropy, defensive stance morph (whichever) and you have room for deep slash, dark shade, and inner beast
rotation: blur morph, pierce armor or inner beast (depending on stam-majicka whichever is highest), darkshades, deep slash, go back to your main bar and keep those up all the time.