i think the only reason they nerfed Rain of Death because now war has a 10% dmg reduction as well, if they kept brd RoD it will be a reduction of 20% (war and brd) + 10% strength from pld which they think its too much on a single boss. So they kept the 10% of war and 10% from pld as a single debuffs.
looking at the bright sidei guess its a save up for the brd TP as well (since it was 200 for brd and now 60 for war with rotation)
the only loss will be on multiple since it is single target debuff now for war