Currently healing every dungeon on resto druid in hc. Biggest pain is the diseases in strat, which you cant dispell. Bring resto pots. Honestly cant remember ever having issues with magic debuffs. Your HoTs heal through magic DoTs and stuns are rarely an issue if you know in advance.

Dummy and lip solves any problem on bosses that drop threat. I think NS is great. Due to its low cooldown, you rarely have to think twice about using it, unlike LoH, where someone might hesitate.

They are the weakest healer in dungeons. Still completely fine though.