There is no good reason that Protection is being removed – leave Protection alone! Introduce War Priest as a new Cleric tree, as Favoured Souls will eventually get Divine Avenger.
While War Priest is a poor attempt at an offensive melee tree, Protection is at least a poor defensive melee tree – why throw away that development time & effort? Protect Protection!
Even ignoring the defensive versus offensive bias of the respective trees, the two trees offer distinct enough differences to warrant both. Protection’s Universal Spell Power is generally more useful than War Priest’s Fire & Light Spell Power. Many of Protection’s abilities work on others while War Priest’s are mostly self only; unlike Protection, War Priest also requires that you actively attack to make the most of your abilities.
Forgoing the in-game distinctions, meta-gaming also requires consideration. Many of us have exhausted our ability to respect our characters and without further means to do so should not be unduly punished.
Please prioritize Protection protection, thank you!