Overhealing is fun. I heal the way I wish the game was. Not the way the game is. If I want to DD, I will queue as DPS.
I am a big fan of the Light's Champion Ultimate (resto). Most of the time I have that slotted rather than Barrier. It can really save the day if you have to res someone or you are just choking hard and need to pad your heals.
If you can sustain it and your DPS are survivable, the Mythic Spaulder of Ruin is a great buff for your team. You do have to give up your 2 piece monster buff though.
If sustain is no issue for your team, Archdruid Devyric's is a great option for monster helm as well. A lot of other options here. Always adapt to the group you get.