That's nice. I thought the ticks start 2-3 secs after placement. Can you really say it's best in the game though? Assylum gives 10% HP recovery bonus to anyone inside, so basically if the raid-wide doesn't kill you get more or less the same value from both. Assylum has a longer cd but it doesn't cost resources and lasts longer as well.
Well... I don't think that's fair.
Whm doesn't have a lot of weaving slots because they don't have many ogds to weave. They have assize, asylum, bene, plenary and temperance. All of them have long cooldown. Divine benison and tetra are almost never used. Usually, if you really want to move or weave more than one ogcd you can just reapply your dot. Only the whm's dot deals damage when cast and I guess it's for that reason. They don't have ruin II like the SCH and 1sec time to weave and move around like AST. You can also use lilies which are the better alternative because you lose only 75 potency per lily whereas the reapplying of the dot is going to cost you 180 damage potency if more than 3 ticks are remaining.
Sch loses 90 potency every time they use Ruin II to weave their heals or move. You would have to use ED to make up for the lost potency which is going to result in you healing less. It's quite noticeable for your co-healer.
Ast is not an exception. They can lose rDPS when their party's dps is bad even if they played perfectly.
Whm has the strongest AoE damage from all healers and there is no point arguing about it. Misery + Assize = 675 +400 = 1075 AoE potency on every mob pack except the first one and that's aside from the Holy spam which stuns targets.
Whm also has the strongest ST healing spell in the game - bene. Aside from that, if you really want to heal someone you can dish out 1900 cure potency on a target in less than 2.5s.
10% damage reduction is not that high, to begin with. WHM has it too. It's on 2 min cooldown but it has 30y radius. People can't stay grouped all of the time in one spot, like for example e12s Shiva's ice pillars. So WHM's temperance has its unique uses.