I actually played a barbarian priest in 2Ed who inspired berserker furies as opposed to Turning Undead. I didn't tell anyone when I designed him...and when they found out?
HOO-HAAAAAH!!!
HOO-HAAAAAH!!!
I forgot to mention: A major benefit of my proposed system is that setting products can introduce unique domains (with unique spell lists) for all their gods. So there could be a "Mystra" domain that has healing spells and mage spells, and a "Talos" domain that has fire spells and storm spells. So it's not like gods have a bunch of generic domains and you pick one or two; in this system, each god has one domain that includes all of their shticks.These are interesting ideas, and this itself is an interesting topic.
However I would like to see some of the Old School ideas about special priesthoods: oftentimes Magic Users were the priests of gods of magic, and certainly Druids were considered the priests of gods of nature. For example Drow priestesses were Cleric-Magic Users, so that Clerics did themselves need Magic User spells.
If Clerics are always the class for the servants of every god, then they will poach on the powers and class features of other classes better associated with such fields, especially domains of Magic, Nature et cetera.
Personally I'd do more than just Channel Divinity. I'd add proficiencies, skills, and items to the domains.
War
Gain Heavy armor prof.
Gain prof. with one Martial Weapon
Sun
Gain Radiant lance as a orison