Warlocks with normal spellcasting? Non-warlocks with pact magic?

[Greywander]

I've done a bit of work on creating alternate magic systems, sometimes for a specific (often homebrewed) class, but often meant to be an optional alternative for existing classes. For example, I've worked on a wild magic system that can, theoretically, be applied to any spellcasting class.

So I was thinking, pact magic already exists as an alternative to the normal spellcasting, so what if you could play as something other than a warlock, but using pact magic instead of the standard spellcasting system? Like a pact magic wizard or cleric? Conversely, what if you gave the warlock normal spellcasting?

I'd consider the warlock's Mystic Arcanum to be part of the pact magic system. Thus, say, a wizard using pact magic would be able to prepare spells 1st through 5th level normally, but can only prepare one spell for each level 6th and up, which may be cast once per long rest. The wizard would get their spell slots back on a short rest, but would still need to long rest to prepare new spells (although you might allow swapping out one spell per short rest or something). Converting a normal spellcaster to pact magic requires that their Mystic Arcanum count against the number of spells known/prepared. Creating a warlock with normal spellcasting adds the Mystic Arcanum spells to their total known spells (basically giving them 4 more spells known).

My first impression is that pact magic doesn't have the same balance as normal spellcasting. I'd generally consider it to be a bit weaker than normal spellcasting, which is why the warlock gets other features, like Invocations. That said, when comparing the number of long rest and short rest abilities of martials versus casters, I've kind of felt like pact magic got a lot closer to what martials get. Making every caster use a pact magic style system might reduce the perceived gap between martials and casters. I think it would also work well if using gritty realism rest rules, as you still get your low levels spells back overnight, but need a week of downtime to get those high level spells back.

Anyway, I guess my question was: How would you feel about giving non-warlocks pact magic? What about giving warlocks normal spellcasting? Is this balanced, or is there a clearly superior choice?

[Callak_Remier]

The issue with why warlock have pact magic is to allow for the strength of invocations class feature to have a meaningful impact.
If you wanted to design a spell casting class with powerful features. I would give them pact magic to allow for that.

[MrStabby]

Yeah, pact magic is a lot weaker than spellcasting, but the Warlock also makes the most of it.

So if you think about your power per turn on average it is the power of each of your spell slots plus the number of turns you don't use resources multiplied by the effectiveness of those resource free turns. The more powerful your resource free turns are the less you lose by having your magic concentrated in fewer but higher level spells.

Something like a lore bard or wizard would really suck with pact magic. A swords bard or moon druid would suffer less.

One thing I have seen with homebrew, it that a lot of people seem to underestimate the power of spell selection. Some spells are great, some are terrible. If you are looking to change magic systems then you want to really carefully look at the spells they actually have. Something like the hexblade would be ridiculously overpowered with normal casting given their level 1 spells include wrathful smite and shield.

On the other hand a lot of warlocks will feel the squeeze on spells known this way. The number of spells a Warlock knows is going to be fine when you only have to attend to spell slots of a single level. If you need to have options for more different levels then spells known becomes more of a constraint.