yeah RDM needs something to hold hate.
<3 RDM tanking, i can remember the time (level 75) when i went to skill up parrying / shield during Sea Horrors hundret fists.
RDM/blm is nice on mobs that don't put out tooooo much damage (hitting for 200+ [before pdt- & shield block]and DA or TA too frequently).Drain adds some good dmg/cure.
RDM/nin is fine for all mobs.
But I always use Genbu's shield as sub because the 10%pdt- and high block rate is nice. ^^

PS: i didn't have the time to read all posts.