I think people are too focused on balance first, then fun mechanics. I think the devs just needs to start with fun mechanics, then check for balance with playtest and polls. See what he did with the Order Domain for clerics in the more recent video: many warlord-themed powers, the class can actually throw a lot of granted actions and yet it doest seems broken or anything, just fun.
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Voice of Authority (Level 1)
You can invoke the power of law to claim authority over others. Once per turn when you target an ally with a 1st level or higher spell, that ally can use their reaction to make a single melee or ranged weapon attack against a target of your choice. If a single spell targets multiple allies, only one ally gains this benefit.
A bit of theory and math.
Spirit Guardians is deemed as a clerics best option. I'm not going to dispute that. I'm going to embrace it. Spiritual Weapon is generally considered the Clerics next best damage spell option and it can be used in conjunction with spiritual weapon.
So a typical level 9 cleric can:
Turn 1. Cast Spirit Guardians
Turn 2. Cast Spiritual Weapon with a bonus action (which lets you make an attack with it) and attack.
Turn 3. Attack and use a bonus action to attack with spiritual weapon
Turn 4. Attack and use a bonus action to attack with spiritual weapon
He has enough spell slots to cover spirit guardians for a whole 6-7 combats but only enough spell slots afterwards to use spiritual weapon 3-4 times.
He can use the level 1 spells for out of combat healing.
Assuming each combat lasts 4 rounds (not a bad assumption) then he will do 3d8 + 12 (25.5 avg) per combat with spiritual weapon. 102 avg damage over a 6 encounter day the day with spiritual weapon.
He will also be able to heal with 4 spell slots at level 1 for 1d8+4 damage. total healing is 34.
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The order cleric will forgo using spiritual weapon and have the level 9 ranged rogue attack as often as possible. A level 9 rouge will do 1d6+5+5d6 (26 avg) damage on an attack. He get's to use this feature 8 times by casting healing word at the rogue even if it isn't needed. That's a potential of 208 avg damage and it can be fairly front loaded as opposed to the spiritual weapon route. It's also more than twice as much potential healing (though the rogue won't necessarily always need healed every time you target him with a healing word to grant him an extra attack).
Both characters can also get their regular attack as damage but it and spirit guardians effectively cancels out for each build.
A difference of 208-102=106 damage per day at level 9 isn't game breaking even if it can be very front loaded, but it sure is starting to look like I have a point about off turn attack granting being problematic with a rogue in the party. Heck take out the rogue and literally have any other class in the party and the subclass probably balances out perfectly or maybe even a little on the weak side.
