Personally, I love what Fantasy Craft did with the archetype in the creation of their Priest class. One thing to keep in mind is that the "power curve" in FC is quite a bit lower than in D&D, especially in magic. For instance a mage can cast "cantrips" at no cost all day long, but don't get access to 1st level spells until 3rd level.
The FC Priest class covers all of your "worship" based archetypes including shamans, druids, clerics, acolytes, mystics and any other "practitioner" of a faith.
Each Faith has a number of Paths (Domains) assigned to it. For instance the Dwarven patron of blacksmiths, warriors, and fathers might have the Paths of Earth, Metal, and Strength associated with it. Each Path then has 5 Steps in it. As the priest gains levels they gain access to more steps. For instance at 1st level the Priest gains 1 Step in any 1 of their Paths.
Paths then offer a variety of different abilities, from bonus skills and bonuses to skills, to bonus Feats to Miracles (aka spells).
This gives the class a unique acquisition mechanic, while at the same time, not reinventing the wheel. Instead of making them outright casters like the D&D cleric, FC Priests have a "Caster Level" equal to their level but not all of them gain spells. which act more like 3E's spell-like abilities) which are often set up as a "per scene" resource (similar to 4E's per encounter). Some of the Step 5 spells, being very powerful are actually only usable once per adventure such as Resurrection for Path of Life 5.
An example of a Step that grants spells:
• PATH OF LIFE 2: You may cast Cure Wounds II and Restoration I once per scene.
For the Dwarven example above, a 1st level Priest would be able to choose Step 1 from one of their paths, which would be:
• PATH OF EARTH 1: You gain the Pathfinder Basics (caverns/mountains) feat.
• PATH OF METAL 1: You gain the Crafting (Metalworking) focus and a +5 bonus with Crafting (Metalworking) checks.
• PATH OF STRENGTH 1: You gain a +5 bonus with Athletics checks.
On top of this, the class then gets a laundry list of Class Features aside from the abilities they gain from their Paths.
For instance:
• Use of a ritual weapon (when it’s lost or destroyed it’s replaced at no cost [after a set condition]).
• Ability to spend a resource (action dice) to re-roll a failed attack with a ritual weapon or a Priest class skill.
• # of times per adventure to ask the GM for a Hint. The GM can refuse and you get a bonus action die instead.
• Bonus Feats (Chance and Style feats only)
• Special Abilities: Priests get to choose 5 special powers from options like: Benediction, Congregation, Rebuke, Turning, Sacred Weapon, etc.
• Bonus to Wisdom (+1 at 10th and 20th)
• Bonus with Will (10th) & Fort (20th) saves to you and allies
And then paths...
• Paths: You gain 1 Step along a Path at every odd level, giving you a total of 10 Steps in any combination from your paths. Most faiths have between 3 and 5 Paths they offer.