Would it be unbalanced to allow non-spellcasters to take the Eldritch Adept feat?

Question

In Tasha's Cauldron of Everything (and the preceding Unearthed Arcana), the Eldritch Adept feat (p. 79) lets the character learn one Eldritch Invocation. However, it has a prerequisite: the Spellcasting or Pact Magic. Hence, it excludes only non-EK Fighters, non-AT Rogues, Barbarians, and Monks.

I understand the thematic reasons for this prerequisite to exist, but are there game balance reasons for it? That is, would it be unbalanced to allow non-spellcasters to take the Eldritch Adept feat? Answers should include example class/invocation synergies.

Answer 1

The feat is balanced on any class because multiclassing exists

The feat is restricted for thematic reasons, well, I can't prove that, but it does make sense at the very least. Regardless, a Fighter, Monk, Barbarian, or anybody else can get this feat simply by multiclassing into a spellcasting class. I can't personally think of any specific Invocations that are alarmingly unbalancing only when held by a level 20 non-spellcaster (at that point, balancing I'd enough of a nightmare already), and I doubt the developers looked that closely at such a combination.

Of course, taking 1 level out of your main progression is a meaningful and steep price, but I can't see that as being a balance concern the developers would've thought deeply (or at all) about.

Of course, it's possible the developers didn't think about multiclassing at all and instead found a problematic combination of features and invocations precisely and only for the non-spellcasting classes. I find this an unlikely enough scenario to conclude that the feat has its prerequisites for purely thematic reasons.

Answer 2

As far as I know the developers have not explained the reasoning behind locking Eldritch Adept behind Spellcasting/Pact Magic, and even if they did it's difficult to know if what they say publicly actually reflects the development process - for example it could be misremembered, second hand information, or perhaps even giving the wrong information on purpose.

As far as balance goes, all we can say is that having the option is better than not having it. Even more than that, some invocations are powerful and unique options that can't be gained through other methods: for example Mask of Many Faces allows Disguise Self to be cast at will, and Devil's Sight allows you to see to 120 feet regardless of darkness (magical or not). These are not features that can easily be replicated through other means so clearly it has some value.

I read through the invocations a few extra times just to be certain, I am not seeing any that would make non-spellcasters over powered. Some of the interactions I found were:

• Armor of Shadows is the best armor for dex characters
• Fiendish Vigor is good to have on a tank at low levels
• Ascendant Step allows essentially flight for non-casters *requires 9 levels in warlock
• Cloak of Flies on a melee high cha non-caster (why would anyone do this?) *Requires 5 levels in warlock

The feat specifically states that if the invocation has ANY pre-requisites you must be a warlock who meets them. This includes a number of invocations which specify the character must be a certain level in the warlock class.