Well...This is the best I got...Haven't looked into the thief as a support class really, so this is a bit new to me.
There aren't many "healing" mechanics, per se, but it looks like the overall support aspects are decent.
http://www.guildhead.com/skill-calc#zckMMzz0MFnrox0a0xckqcVkb
Daggers should have the Rune of Intelligence (Next strike after swapping to this weapon is 100% critical)
Pistols should have Rune of Hydromancy (Swapping to this weapon freezes nearby enemies in place for 3 seconds)
Armor: Runes of the Thief (Crit and Condition Damage, +10% damage when flanking or behind a target)
Carrion Jewelry? (Condition Power Vitality) Berserker? (Power Precision Vitality, Crit damage)?
Logic / Use:
The build is centered around entering your allies into stealth and stealing as often as possible, and stacking the hell out of your "opener" (time immediately spent after stealing) with buffs, debuffs, and around an additional 30%-35% damage (10% from flanking with Runes of the Thief, around 10% for Lead Attacks (only in the beginning), and an additional 10% for exposed weakness).
You have 4 mechanics to enter into stealth:
Cloak and Dagger (Dagger offhand skill) - Costs initiative
Hide in Shadows (heal) - 30 second CD
Shadow Refuge (Utility Skill) - 60 second CD
Blinding Powder (Utility Skill) - 60 second CD
Blinding Powder and Shadow Refuge can enter allies into stealth as well...
When you enter your allies into stealth, they:
Gain regeneration.
Each time you steal you:
Reset the CD on one type of skill (random)
Gain 3 initiative
Deal damage to the target
Daze the target
Apply poison to the target
Apply weakness to the target
Grant Vigor to you and your allies for 15 seconds.
"Steal" two boons from your enemy and grant them to allies.
Grant Fury, Might, and Swiftness to you and all allies for 10 seconds.
So the basic flow of combat would go something like:
Stacking bleeds from range via pistol till...
Max initiative
Body shot (To inflict Vulnerability)
Stealth
Steal (boons!)
Swap to daggers
Backstab (Crit!)
Random fighting goodness
Cripple (Dancing Dagger / Caltrops)
Weapon swap to Pistols (freezes enemies in place)
Retreat
Step 1
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This actually sounds like a pretty fun build to me. Lots o mugging. Nice 10 seconds of ridiculousness, then back to controlling the enemies. And approximately every 30 seconds you can grant Regeneration ( via Allied stealth utility skill), Fury, Might, Vigor, and random boons to allies.
For slightly more damage, swap out Assassins Signet into Caltrops. Activate Signet before backstab. If it stacks, it means you daze the target, get a 150% backstab (which is 200% damage to begin with, yielding a 300% damage strike), CRIT with it (150% + prowess, yielding, if multiplicative, a 450% damage strike + prowess), possibly paralyze the enemy for 4 seconds (if Panic Strike is off CD and damage is high enough), Then have all that time to tear into them while your allies and yourself are buffed with Fury, Might, Vigor, and those 2 random boons.
Also they're bleeding. And poisoned. And weakened. And vulnerable.
Like a bad trip to Mexico.
Now, if you REALLY want to just be a healer...you could take points out of deadly arts and put them into shadow arts for the additional 200 healing that would go into Shadow Refuge, but it seems (on paper) like a huge sacrifice of power for a minute increase in group healing.
(Also, I can't guarantee the math will all add up like that. For all I know they don't multiply things like I wrote out above. But it'd be damn awesome if they did though. Hoping.)
~Dash
