Is this homebrew Spiritual Shield spell balanced?

Question

I have a pacifist Cleric in my party, so I created this spell to replace spiritual weapon for him:

Spiritual Shield

2nd-level evocation

Casting Time: 1 bonus action

Range: 60 feet

Components: V, S (Note: I don't really hold my players to components, so I don't really care about this part for balance.)

Duration: 1 minute

You create a floating, spectral shield within range that lasts for the duration or until you cast this spell again. The caster must specify a target when first casting the spell. It can target any creature, hostile or not, and does not require a saving throw if the target is hostile. If the shielded creature moves on its turn, the shield moves with it. As a bonus action on your turn, you can move the shield to another creature within 20 feet of the first creature. The shield can appear however you wish, and its stats do not change based on its appearance. The shield can have one (1) of the following effects:

• The target’s AC is boosted by +2, as if they were using a shield, but without the requirement of actually holding one.
• The target gains resistance to one of the following forms of damage: necrotic, poison, or psychic.

At Higher Levels: When you cast this spell using a spell slot of 3rd level or higher, the target gets a +1 to AC for every two slot levels above 2nd, regardless of initial impact chosen.

Is this an acceptable replacement for spiritual weapon? If not, how do I make it so?

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My thought process:

Spiritual Weapon does damage equivalent to common weaponry, so I designed Spiritual Shield to give the same bonus to AC as given by a regular shield. It has the same components and basic requirements as Spiritual Weapon. It is designed to be as close to a 1-to-1 exchange as possible.

Answer 1

The base spell is fine, but the scaling AC is probably too much.

If we compare this spell to the 1st level Shield of Faith, then it has a few advantages:

• it doesn't require concentration
• you can change the target

It also has the disadvantage of not lasting as long, and it's a level higher. That seems about right to me.

The alternative use of warding someone against an energy type also seems about right; if you compare it to Protection from Poison then it has shorter duration and less effects, at the advantage of being moveable to others. The other two damage types are probably also okay. Note that Protection from Energy is a 3rd level spell, but then it works against the more common damage types, so that's probably fair.

The only thing that might be an issue is the rising AC bonus. Due to bounded accuracy, a +2 AC is a good thing to have at any level. None of the other AC-boosting spells scale with the level you cast it from, probably for that reason. Adding a high level version of this spell to an already well armored character would make them all but untouchable.

Answer 2

It's pretty balanced, but Spiritual Shield + Spiritual Weapon is too much.

Concentration exists to keep too many effects from occurring on the battlefield at the same time, because that gets hard to track. Spiritual weapon is nearly unique in providing a substantial ongoing combat benefit that doesn't require concentration. I don't think you should introduce a second spell like this. This spell is even more work to track than spiritual weapon is. Spiritual weapon doesn't have any passive effects-- its existence only matters during the caster's turn. This spell can matter on anyone's turn.

In addition to other's recommendations to remove the scaling AC, I recommend that you maintain the number of effects that low-level clerics can have active at one time by changing the first line to "You create a floating, spectral shield within range that lasts for the duration or until you cast this spell again, or until you cast spiritual weapon."

Answer 3

You Must Consider Concentration

In terms of character optimization, Concentration is something that must be considered in balancing spells. Concentration was imposed in order to stop the 3.5e problem, where casters would throw on multiple (sometimes dozens) of stacking buffs before going into battle.

Basically, we don't want to re-create CoDZilla. With enough Concentration-less buffs, this could be done, especially with something like a Sorlock or Sorcadin.

All that being said, this is a relatively mild buff (giving effectively an Animated Shield for a Level 2 slot that lasts for only a single combat). I'm not sure how much of an issue it will be in practice. Might be worth playtesting to be sure.

I believe that this would be easier to balance if it were to require concentration - but then it might even be a little weak. Shield of Faith has a (Concentration) 10-minute duration and is a level 1 spell. I don't even think that Shield of Faith is a great spell for its level, because it's overshadowed by the exceptional Sanctuary and Bless. Maybe if you up'd it to Duration: (Concentration) 1 Hour?

I don't think that the scaling armor is a problem because it doesn't stack with a sword-and-board Warrior, and because actually using the scaling will require that you burn a high level slot for a spell that only lasts for 1 combat.