I was also going to stay out of this conversation, but the whole point of Ruin II:s NOT spammability,even at the start of fight, is missed by the OP. Blind. I'd honestly rather leave blinding to the tank who in most cases knows when he'll need the debuff more than when we feel like "hey minor increase in dps WOOT WOOT imma steal this debuff slot now kkkkkkk?" Yeah, none of that for me thanks, we are thought as the retards of dps community enough.
On general opening rotations, I go with what Kevee has found out wayback when, Bio II > Miasma > Bio > Fester > thunder > Ruin then go with what drops of and / or bane contagion etcetc is needed.