I would rec running this
RoR.builders - Warrior Priest. Ignore Sigmars vision, Absense of faith and soul fire until you have spare points. Your primary ability in SC's, because you will get destroyed in RvR is Sigmar's Radiance, and on cool down Divine Assault. Make sure you keep detaunt casting constantly, and use Sigmar's Shield when taking a lot of dmg. The other spells mentioned previously not to take unless you have spare points, are for 1v1 situations or when you don't really need to do much healing.
In terms of renown, invest in reduced crit chance, dodge/disrupt and parry.
In terms of gear, I would rec Dominator + genesis warrior. With 4 armour talism and 4 wounds talism. Your goal is to be tanky to heal for as long as possible, rather than doing high dps and doing perhaps tons of healing in a short lifespan. Also get the 2H emblem weapon that gives the most strength etc. The RVR one will do but for a melee WP it's vital to have the best equipment possible. I would suggest not running a melee WP until you have most of this equipment, so just run a healbot till then.
In terms of best aura, armour is the best as it has 100% uptime and is always useful. Second best is the DPS aura, whenever someone attacks it has a chance of doing spirit dmg to the target. Last is the heal aura, the reason this is last is because even when it fires, you may already be at 100% health and therefore it is a waste, compared to dmg which is always useful.
P.S You may be wondering why I've chosen heal reduction tactics. These only reduce cast heals. Sigmar's Radiance and Divine Assault are life steal. Also changes to this I may support is equipment that gives more AP/s as you will burn through them fast, and potentially crit reduction from an initiative talism, but as long as you are below 10% chance to be crit hit you are fine.