Class Mastery
The Warden's Class Mastery Passives are incredibly useful:
Nature's Bounty activates on overhealing any one person with a Green Balance ability and provides everyone with major heroism for 4 secs.
Tundra's Maw debuffs enemies with major brittle for 2 secs on applying chilled to them, which is done with Winter's Revenge/Ice Elemental Blockade on the back bar.
Sets
Pillager's Profit is on the body so either ult will grant 50 or 60 ult to each person in the group. This has to be done with 500 ult but with major/minor heroism, decisive trait and light/heavy attack ult regen, this shouldn't be too much of a problem. In an ideal ult drop, you are the last person to use their ult so everyone else gets theirs back faster. To keep track of the 45 sec cooldown, I recommend using Cooldown Tracker to set a 45 sec timer on the Pillager's effect.
Powerful Assault procs with Echoing Vigor on the back bar Ice Staff (to help with chilled procs for Tundra's Maw). Vigor has to be cast twice as Powerful Assault can only target six people at a time. I would recommend using Group Buff Panels to get a table of the group and it will tell you who has and hasn't got the buff active.
Ozezan procs on overhealing which is simple enough.
Skills
Winter's Revenge and Expansive Frost Cloak are slotted on different bars to keep up the increased chance of proccing the chilled status effect for Tundra's Maw.
With Budding Seeds and Lotus Blossom, Nature's Bounty should be easily procced as well.
As mentioned above, Vigor is a nice HoT and procs the powerful assault weapon and spell damage.
The Illustrious Healing morph uses smart targeting rather than picking and sticking with the first 6 people in the aoe.
The rest of the skills are all self-explanatory 🙂