'HEALS on WHEELS' Build
It became quite popular to name your build and so I decided for the name that would express the way I feel about it - lets call it 'heals on wheels'. There will be literarly circles of healing around you and your allies, and everyone will keep rolling through the dungeon!

So, the build was created in order to play in group (PvE) as a healer. It has several advantages. First of all, it has significant burst heal (Breath of Life or BoL), which can be improved further by positioning your allies in the 'Extended Ritual' circle. This strategy is twice as useful for bosses such as Valkyn Skoria (CoA), unless there is a vampire in your group (nothing helps basically). Disadvantages: Note that the build is dependent on positioning of your group, since your heals (apart from BoL and Repentance) are place-oriented. In heavy fights where you need to move a lot, its recommended to replace 'illustrous healing' with some other healing over time (HoT) spells, such as 'Rapid Regeneration', or healing shield ('Ward Ally').

Casting BoL while having your allies in the circle gives huge amount of bonus to your healing spells. Even if the bonus does apply only to healing spells from TP skill line - i.e. not to healing staff skill line, its a significant game changer. In many situations it is essential to run into your group though in order to reach this bonus. You should do it even if there are mobs around your allies (thats a more aggressive healing, but works quite well). Indeed healer is quite fragile here - so backing off a bit, fast, and keeping your distance from mobs is essential - it gives you better overview of the battlefield too. If the group is being attacked by extreme amount of mobs, healer can start by spamming 'illustrous healing' (extended duration morph from 'Grand Healing' spell) first. A kind of situation when you have to think a bit in advance and prepare yourself . With all your defenses at place - you could even start doing some damage (spears) and hiting repentance every now and then (it heals + gives stamina and stam. regen to your allies). It is basically a heal for free! (in a case there are already some dead mobs). More importantly, do not wait with your repentance for the mobs to stack - cast it even if there is a single dead body. Boss strategy is pretty straitghtforward - place your regen aura under your feet and heavy heals should (in an ideal situation) be followed by heavy attack (to refill magicka pool). Keeping your magicka pool full can get pretty complicated, especially if your group has difficulties avoiding area damage - drink even when you are full magicka. You will not run out and ppl will die only rarely (one shot situations). Last but not least, keep 'Radiant Oppression' on your skill bar. Even though you will miss the chance to use it on group of mobs (its a bit messy) - it is invaluable finnisher for bosses that are not in their 'rage' phases. It happens so often that radiant oppression is being cast (channelled) while your ally is suddenly receiving huge amount of dmg ('oh sh*t situation') - in such situations you can interrupt the cast of radiant oppression by blocking.

Altogether, this is not a 'two button' healer's build, rather, the success of this build depends on how you are assessing the situation (you have two different ultimates, one defensive, one offensive). It takes a bit of time to master but its fun to play and from my experience, it is also less stressful since the health of your allies are less 'jumpy'! You know what I mean! ;)

I hope this helps! Cheers!