How unbalanced is it to hand out Feats/ASIs in place of Magic Items?

Question

During a quest (probably at a point of narrative significance, like a god rewarding a player character with power for defeating some big bad or something like that) would it be unbalanced to reward a PC/the PCs with a Feat or ability score increase (ASI) instead of a Magic Item?

My thinking is that since Magic Items (usually higher level ones) can sometimes give attribute boosts (Gauntlets of Ogre Power, for example) and other Feat-like advantages, how does that compare to actual Feats or ASIs?

If I try to anticipate some answers, I'm thinking that Magic Items can be sold, or passed between the party (attunement notwithstanding) whereas Feats/ASIs are permanently attached to the PC and can never be taken away.

On the other hand, some Magic Items increase an attribute to 19, whereas an ASI on a character whose highest stat is 16 or 17 isn't really going to change the end result; they still end up with a +4 modifier.

At lower levels, the Magic Items won't be as powerful, so handing out Feats and ASIs will be unbalanced. But at higher levels, doesn't this balance out?

Note that I haven't told my group yet (and I have no specific plans to do so), this is simply something that has occurred to me (maybe something to base a quest around) and wanted more information before I commit to this idea.

Specifically, I'm not interested in opinions, since ultimately I can do whatever I like in my games, regardless of how stupid my decisions may be. I am interested from a balance perspective:

How do the two options scale against each other?

Do rarer Magic Items balance against Feats/ASIs or will Feats/ASIs always give the players a stronger mechanical advantage at any level?

Answer 1

The DMG contains a section "Other Rewards" (starting at page 227) which includes amongst other options:

• Blessings of the Gods, which usually mimic the properties of a Wondrous Item
• Charms, which usually grant spell-like abilities or potion effects
• Special training, which grants a character a new feat or skill.

So what you're asking for seems to be a perfectly acceptable way to do things, and you can probably get some more Inspiration from reading that chapter.

Answer 2

While you can certainly do this according to the DMG (See Erik's answer for details), keep the stacking in mind.

When you give the player magic items, those will replace other items they currently use. Reasonably powerful magic items will also take one of the three attunement slots.

When you give the players inherent character upgrades, those will stack with those three magic items and with their usual character advancement.

To keep the campaign balanced, you might want to be extra stingy with magic item rewards throughout the whole campaign. Alternatively you could house-rule that these divine rewards also take attunement slots.

Regarding the permanence vs. transience of character feats vs. magic items: Keep in mind that when you are playing in a campaign world where deities can bestow new feats and ASIs on people, then it isn't far-fetched that they can also take them away. Don't be afraid to make use of this if some of the boni you handed out turn out to be too powerful.

Malicious deities might even curse people with permanent attribute decreases or taking away feats and even class features from them. But this kind of divine punishment through DM fiat is something which should be used very sparingly, as it can easily be seen as abusive DM behavior.

Answer 3

Giving feats instead of magic items is fine

For weapon users, an ASI is much less useful than a simple, uncommon +1 sword. For casters neither matters much.

Weapon users

For pure DPR, +2 for your attack attribute is identical to a +1 magic weapon, both increase your attack and damage by one.

If you are Dex primary, an ASI also gives +1 to AC, initiative, a common save, and several skills. With Str the side benefits are not nearly so good. +1 to a less frequent save, and a single skill.

A magic weapon however gives you full damage against all monsters. In my opinion, this alone outweighs any side benefit an ASI might have.
Without it the most optimized barbarian is mostly useless against a CR2 Wererat.

Casters

Most spells don't add your primary attribute to the damage, only to the attack bonus or the DC, so ASIs are less crucial to begin with.
Most damaging spells deal half damage on a save, reducing the importance of a high DC even further.

Offensive magical items like Wand of the War Mage are limited in their application, giving +1 only to attacks, not for damage or DC.
Wands on the other hand provide versatility, effectively giving you a spell known and many extra slots. You have to attune them, still much more useful than any feat or ASI (with the right spell inside).

Diminishing returns

An ASI is great when your main attribute is 18, significantly less so when it is already 20. Sure, it depends a lot on your class and build, a Monk or Paladin seemingly can't get enough of them, while a Rogue has plenty.

After a Wizard has Int 20 and Resilient(Con), there is not much to gain.

Conclusion

Most characters are the strongest if they have a combination of ASIs and magic items.
Once I have a +1 Longsword on my Fighter, another one does not help much, and even +2 one is only a small step up. Here I would prefer an ASI.
If my druid has Wis 20, a Wand of Web is much more valuable to me than any feat.

My point: giving magic items is perfectly fine, and ASIs are weaker, so they can't upset the balance.

Answer 4

Among the magic items listed in the DMG are (effectively consumable) Manuals, one for each ability score, that increases the ability score and its maximum by 2 points each. These are listed as Very Rare.

An ASI is slightly more flexible since it can be split up, but in practice each character will only do this once if at all over their career. Otherwise, the increase to the score maximum makes the Manuals more powerful than an ASI.

As @KorvinStarmast points out, Ioun Stones are other magic items that provide a similar benefit, granting +2 to a specific ability score (but not its maximum), and are also listed as Very Rare. These have the extra drawback of requiring attunement.

I'd rate a hypothetical ASI/Feat boon as between these two established items in power, so it would also be equivalent to a Very Rare treasure.