I combine Templar healing with restoration staff.
Lead with regeneration/mutagen because it has a nice long duration, always cast it twice (so that all four party members get it) especially while moving into an oncoming fight.
Once you arrive at the fight, cast Purifying Ritual to create a large circle of healing with a synergy that players can use to heal themselves if they return to your position needing healing. Don't be afraid to cast Purifying Ritual again as the battle moves to a different location.
Healing Springs is great for stacking heals on someone at low health, cast it multiple times when the party is really doing bad.
And of course your emergency heal, is Breath of Life, use it the least because it's expensive, but it is very effective on short notice.
You're not so much using a rotation, as you're setting up shop and then applying more heals as needed. If you're back bar is for combat, you only really need Breath of Life on that one, you'll use it a lot when the team doesn't need much healing at all and you feel like fighting.
Those are the only four heals I use, except for Purge, which you get from PvP Support skill tree, it removes negative effects on the team that would otherwise gobble up all your mana doing healing. By no means exclude other heals you want to add to your style. Source: primary character is a level 1008 templar healer.
PS: Ritual of Rebirth is nice now that they've removed the casting time. I never used it in the past because of that delay. They buffed it because no one was using the basic healing spell of the game lol.