So, some context first: I'm not the only dm who doesn't trust their players with T1 and T2 classes, though with my group its more about overshadowing eachother than much munchkinning or abuse. Still, I've had a ban on clerics, sorcerers and wizards since the beginning, and have been grudgingly allowing the Oracle for short of a better option.
Now, the Reliquarian Archetype from the latest player companion seems pretty perfect to me. It's an Occultist archetype exchanging the second implement school from first level and its SAD-ness for a Cleric domain and counting as a divine caster. As I see it, a pretty good way to make it work A La the elvish lorekeeper Oracle archetype as a mystic theurge.
Anyway, the reason this is in the S/HR/H forum and not the advice is the following: some ideas at focusing and boosting the Reliquarian a bit more towards the Cleric, Oracle and old-school Archivist respectively. These were made pretty late and are more theories at this point than finished products, but...thoughts? (Also, the Reliquarian can only take one of the three options, of course).
Divine font: At 6th level and again at 14th, the divine font may choose to gain an additional Domain instead of an additional Implement school. Your level for the purpose of access to spells and abilities from this domain is equal to your level -3. In addition, at 1st level then increasing 1d6 at 5th and every four levels after, you gain the channel energy ability of a cleric.
Divine conduit: Instead of gaining a cleric domain, you gain a Mystery as with the Oracle class. At 3rd level then every 4 levels after, the Divine conduit may choose to gain a Revelation of their mystery instead of a new focus power. Any reference to Charisma in these powers is instead switched with Wisdom, and vice versa.
Divine Mind: The divine mind casts his spells as if they were both divine and psychic, and requiring both types of components. In addition, at 6th level you gain a “Dark Knowledge” pool with points equal to 2+ your INT modifier. As a swift action, you may spend a point from your Dark Knowledge pool to identify a creature. Make an appropriate Knowledge check at DC 15. If you succeed, you gain all appropriate knowledge about the creature. In addition, you gain a +1 insight bonus to attack and damage rolls against this specific creature for every 5 by which you exceed the DC for the rest of the day. This replaces the Implement schools gained at 6th level and 14th.