The Paladin’s ability to Smite is considered fairly powerful, isn’t it? You can spend a spell slot and do extra damage on a hit. Imagine you got a magic item that gave you the ability to Smite like a Paladin – you get to emulate a class ability without having to take levels in that class. That sounds pretty powerful to me. You’d figure this has to be a very high-level item, and probably one that requires attunement. But what if neither of those were true? What’s more, what if you didn’t even have to keep the item – you could get it, use it once, then either destroy it or give it to someone else who might be able to use it to gain the ability without compromising your ability to use your copied ability.

Surely that sounds too good to be allowed. But it’s basically what spell acquisition is like for classes like the Wizard – they get an enemy’s spellbook, copy out the interesting spells, then they can trade it around the party or any other friendly wizards before selling it or hiding it somewhere as a backup or burning it or just putting it back in the dungeon where they found it. And they still have the new spell.

OK, so it’s just Wizards who are overpowered this way, right? Well, it’s true that some spellcasting classes can’t increase their spells known this way – Bards, Sorcerers, and Warlocks are all limited in how many spells they know, which is strictly determined by their class levels – they can’t push past that, so picking up new spells (and emulating or surpassing other class’s abilities) requires them to make a sacrifice of comparable class resource.

But other spellcasters have it easier than Wizards – Clerics and Druids for example don’t have to wait for the DM to provide a spellbook in treasure troves or with enemies, nor do they need to do anything else in play or even in character building. All they need is for one of the players in the group to have access to where the spell was published, and all the Cleric and Druid spell lists expand there and then; barring pushback from the DM these classes can prepare and start casting the new spells after their next long rest.

To be clear I think this is a mistake – I don’t think characters should so easily expand the range of their abilities, not just because there’s a real lack of quality control in the design of spells (Lemonund’s Tiny Hut and Banishment come to mind in core books, as well as spells like Silvery Barbs in expansions) but also because the increase of spellcaster power acts a bit like inflation. It devalues characters who don’t get those sort of free expansions.

I’m still thinking about ways I might want to address this, but I don’t have anything concrete yet. I guess that makes this post not a house rule as such, but rather the seed which will hopefully grown into one.