If Warpriest ever gets implemented, this is what I imagine it could look like. It needs to be combat focused as compared to Radiant Servant, which is healing focused. At the same time it needs to be strong enough to be a viable alternative and provide solid group contribution.

In summary, Warpriest Prestige should focus on the Cleric and everyone around him/her stronger offensively and more sturdy.

WARPRIEST I
Usage: Passive
Cost: 4 action points
Progression: 16 action points
Requires One of: Follower of the Lord of Blades, Follower of the Vulkoor, Follower of the Silver Flame, Follower of the Undying Cout, Follower of the Sovereign Host
Requires All of: Empower Spell, Cleric Smiting I, Divine Cleansing I, Divine Might I

You faith grants you divine fortitude, you gain an addition 20 stacking bonus to HP and +2 sacred bonus to saves, and your turns regenerate over time (1 every 2 minutes).

This enhancement automatically grants access to the following:

Aura of Valiance
Expend a use of turn undead to produce an Aura of Valiance effect on yourself. Allies within your aura gain 10% Sacred Bonus to Fortification, and +2 sacred bonus to Hit and Damage.



WARPRIEST II
Usage: Passive
Cost: 2 action points
Progression: 42 action points
Requires One of:Bladesworn Transformation, Silver Flame Exorcism, Undying Call, Unyielding Sovereignty, Vulkoor’s Avatar, Cleric Charisma II
Requires All of: Cleric Prayer of Increidble Smiting I, Cleric Prayer of Smiting I, Cleric Warpriest I

Empower metamagic now grants you 75% bonus instead of 50%. Your divine fortitude now grants you an addition 20 bonus to HP (for a total of 40). Your Aura of Valiance now grants 25% Sacred Bonus to Fortification and +4 Sacred bonus to Hit and Damage.

Spiritual Weapon
Expend a use of turn undead to create a group of spiritual blades that spins about, causing 1d3+1 caster level untyped damage to enemies it encounters. The spiritual blades will only attack enemies that have been damaged, and will not attack fascinated or mesmerized foes, and always attacks the enemy with the fewest hit points in range. All threat generated by the blades are applied to you. (Duration 300 seconds)