The damage Life Shift deals to you is Death Damage, but the healing portion is life-based. The healing component benefits from Natural Awareness because the heal is life-based. And it benefits from Circle of Life by dealing damage. Unless something changed between Beta 6 and Open Beta. I'll check later this afternoon when I get home, but it should still be the case. It benefits from Call of Spring simply be being a healing spell of any sort.
As for Leeching Flames and Mana Wrench, I can't speak for Leeching Flames, but I'd assume its effectiveness really depends on your mana pool, which could potentially be great damage, but after messing around with a pure Dominator build, Mana Wrench does horrible damage. You could probably make deal more damage and gain more mana by spending a global cool down on Reclaim Power or Sacrifice Life: Mana and continue DPSing.
Searing Vitality's definitely not a bad DoT, but Necrosis and Dark Touch are stronger, and Life Leech is about the same, but also causes additional self healing.
With a Life Shift build, you'll be taking decent damage every now and then. Having Life Leech (Improved) and Withering Vine compounding its self healing on top of the passive self healing from Radiant Spores and Lifegiving Veil.
Having Transmogrify will definitely be a bonus, but with the number of two-soul mage builds going around, I suspect we'll be having a lot of transmogrifying people running around as is. But who knows?
Again, this would be a build for more personal DPS plus having the option of a spammable heal.
If you wanted to keep it simple, you could simply stick with your build, use the Archon for the buffs and utility, and use Dominator for the support, and stick with dealing damage with your Life spells almost exclusively. The passive damage that Lifegiving Veil causes is much greater when you deal life damage, so it may very well add up.
Memory Wipe DOES sound nice, but I just don't know how healer threat will be like at end game, so I just don't know if it's worth 10 points spent in Dominator. At least for this build.
Lastly, I cannot say for sure, but generally speaking, health pools (other than that of the tanks') generally don't matter in PvE for most MMOs. Chances are, if you pull threat, your clothy butt's going to get one shot anyway. Raised in Nature will probably be more attractive for PvP.
For a purely support perspective, I might roll with this build: http://rift.zam.com/en/stc.html?t=0zzR_.hMeoMfVo0r.xdIuqVcooo
It's essentially a Chloro/Archon dual-soul spec (you can grab Dominator as your third soul just for Transmogrify if you want.
The basis of the build is to get the RIDICULOUS cast speed buffs, mana reduction and damage boosts from the Altruist, Speed in Numbers and Power in Numbers soul points with all the Archon auras you'll be keeping up. Apart from your Archon auras, you'll be pretty much be playing as a pure Chloromancer (keep Searing Vitality up and only cast Pillaging Stone to maintain your stacks of the buff). But with those three soul point things, your spells will cost quite a bit less, cast quite faster, which directly relates to more damage, and thus, more healing, and you also just get quite the nice pure damage boost as well, which also means more healing.
You can juggle the two points from Swift Thoughts to Enduring Tether, but Soul Tether's quite situational to begin with, and at a 5 minute base cool down and 4 minute cool down fully talented, it probably won't make or break an encounter.
Just some thoughts.
I've been toying around with the Chloromancer since they first officially released hard information on the class.