Giving Githzerai mage armor instead of shield, how goes?

[Witty Username]

In 3.5, githzerai had an ability called inertial armor (or the psionic handbook version had access to a power called inertial armor) that was very similar to mage armor, and I thought having access to a mage armor effect on self would fit better than a once per day shield spell.
How would swaping shield for mage armor work in terms of balance?

[nickl_2000]

I don't see an issue personally. They are both level 1 spells and both available through feats.

[da newt]

Assuming you mean for a playable race:

I'm not sure I can directly answer your specific question, but Lizard Folk have Natural Armor which gives them a base 13 AC, Draconic Sorcerers have base 13 AC, Warlocks can take Armor of Shadows for at will Mage Armor, and those certainly haven't broken the game in any way.

I'm sure there are others I haven't listed.

[x3n0n]

Assuming you mean for a playable race:

I'm not sure I can directly answer your specific question, but Lizard Folk have Natural Armor which gives them a base 13 AC, Draconic Sorcerers have base 13 AC, Warlocks can take Armor of Shadows for at will Mage Armor, and those certainly haven't broken the game in any way.

I'm sure there are others I haven't listed.

Githzerai in specific already can cast Shield once per long rest starting at 3rd level. I think OP was asking for opinions on whether that could safely swap with Mage Armor.

OP: as others have said, I don't think that breaks anything balance-wise.

NB: 8 hours is not guaranteed to cover an adventuring day (that is, if you cast it in the morning, you won't be covered at night), and you have no slots that could be used to re-cast. This is slightly less painful here than with (say) Magic Initiate, since your casting would be subtle, so you can put it off until things look dicey.

[Droppeddead]

Balance-wise I'd say that Shield is better and more useful for most races. Anyone wearing any kind of armour has no use for MA unless you need to go somewhere where armour isn't allowed or you cast it before you go to sleep. I see no problem switching out Shield for MA.

[Witty Username]

Assuming you mean for a playable race:

I'm not sure I can directly answer your specific question, but Lizard Folk have Natural Armor which gives them a base 13 AC, Draconic Sorcerers have base 13 AC, Warlocks can take Armor of Shadows for at will Mage Armor, and those certainly haven't broken the game in any way.

I'm sure there are others I haven't listed.

Yes, I was thinking of the playable race option in Morde's Tome of Foes.

[Luccan]

In 3.5, githzerai had an ability called inertial armor (or the psionic handbook version had access to a power called inertial armor) that was very similar to mage armor, and I thought having access to a mage armor effect on self would fit better than a once per day shield spell.
How would swaping shield for mage armor work in terms of balance?

It's one less spell known on Sorcerer or Wizard, since it lasts long enough you usually won't need it twice. Most other characters won't have as much use for it as Shield. In other words, it's probably a worse pick most of the time, but useful and not imbalancing even on the classes it's really nice for. The thing to keep in mind is Gith are already kind of meh for a racial pick and Mage Armor replacing Shield doesn't do them many favors

[Samayu]

Shield is usable by anyone, while Mage Armor is only usable by someone who isn't wearing armor. So in that respect, it's a much worse pick. But if you had an unarmored Gith, Mage Armor is a better pick than a once-per-day shield.

[Luccan]

Oh, another thought. Githzerai aren't a great pick for Monk, but if you wanted to go for something weird like Strength Monk with a lower Wisdom, I suppose Mage Armor could make up for your AC deficiency as a result. Of course you'd be worse at everything else Monk, but if you just really needed to make the concept work...