D&D 5E Double casting feedback? (with concentration limits)

[Quickleaf]

What if a spellcaster could cast two spells on their turn, with the caveat that the total spell slot level couldn't exceed the maximum spell level they can cast, that only one of the spells can require concentration, and the maximum damage per round is capped at whichever spell deals more (or any) damage?

For example, a 3rd level mage might simultaneously cast burning hands (1st level) and faerie fire (1st level), calling it "glitterdust" or "fey hands of true flame."

Or a 7th level mage might simultaneously cast shatter (2nd level) and mirror image (2nd level), calling it "mirrorburst" or "break the veil."

Would this be totally broken?

Would this house rule fit one of D&D 5e's classes better than others?

 

[Mort]

What if a spellcaster could cast two spells on their turn, with the caveat that the total spell slot level couldn't exceed the maximum spell level they can cast, that only one of the spells can require concentration, and the maximum damage per round is capped at whichever spell deals more (or any) damage?

For example, a 3rd level mage might simultaneously cast burning hands (1st level) and faerie fire (1st level), calling it "glitterdust" or "fey hands of true flame."

Or a 7th level mage might simultaneously cast shatter (2nd level) and mirror image (2nd level), calling it "mirrorburst" or "break the veil."

Would this be totally broken?

Would this house rule fit one of D&D 5e's classes better than others?

This WAS a thing in 3e - with the Haste spell. And it allowed the wizard, already a strong class, to easily break the action economy.

One of the most agreed upon changes for 3.5 was eliminating Haste's ability to cast 2 spells a round - it was just that broken.

Casters already have a leg up, to allow casters to routinely and easily break the action economy? IMO it would be a REALLY bad change and not lead to anywhere good.

 

[NotAYakk]

The power budget of a spell in combat comes from two sources. The first is the slot level, if any, expended. The second is the action expended.

For a spellcaster, the floor on the value of an action expended is a cantrip.

So, casting a 3rd level spell has a power budget of (action, at least cantrip)+(3rd level slot).

Not all spells are maximally efficient but that is their budget.

If you can cast 2 spells, your total budget for your turn is now 2 actions plus the value of both slots.

Using the DMG guidelines, the value of a slot ends up looking close to linear; if you subtract cantrip damage (of a cantrip around the level you get the spell) from a slot's damage budget, you get a pretty strait line.

So by doubling the action portion, this is a significant boost over the baseline.

You can see this with magic missile. A L1 slot produces 3 shots; each level after that adds 1 shot. The power budget is 2 shot for the action + 1 shot per slot level.

Fireball is 5d6+1d6 per slot level. It is, however, described as atypical in its power spike when you get it.

But, by duplicating the action budget, you get more yield out of spells than you would otherwise.

Now, the action budgetbof spells seems to be based on the level you get the spell, roughly. So lower level spells have a worse action budget portion.

But that ends up factoring into spellcaster overall power; the fact that low level slots age out.

We can patch that by requiring higher level slot expenditure; to cast two low level spells as a combo, you need to burn a single high level slot.

Takebdouble MM. Two LX casts in one action is the same as a 2X+2 cast.

For fireball, two level X casts does 10+2X dice, or the same as one level 5+2x cast.

While you did patch damage away, damage spells are mostly just easier to analyze; non-damage are just as good.

My point is the fair slot cost looks a lot like (add up base levels of spells)*2. Then any "at higher level" gets applied to each individually.

So want to cast a L1 and L2 combo spell? L6 slot please.

If cast at level 7 slot, you get to use 1 higher level effect from one of the spells.

Or, in other words, what you described is crazy strong.

 

[Quickleaf]

Mhmm. I see that. I do like the creative space this opens up & I like that it might encourage more spell slot expenditure. I'm still figuring out where this idea could fit, but maybe some kind of limited use... like for a wizard replacing their 1/day use of Arcane Recovery?

 

[Lojaan]

Mhmm. I see that. I do like the creative space this opens up & I like that it might encourage more spell slot expenditure. I'm still figuring out where this idea could fit, but maybe some kind of limited use... like for a wizard replacing their 1/day use of Arcane Recovery?

What is the problem you are trying to solve?

 

[CleverNickName]

It's an interesting idea, but I think it's overpowered. You would have to find some kind of way to balance it out...maybe one of the spells has to be a cantrip, or both spells must be from the same school of magic, or the caster needs to make a Hard (DC 20) or Very Hard (DC 25) Arcana check to pull it off. Or all three.

I think it would be better to take two spells and combine them into a single new spell, using the Downtime rules for "Research." You would work with the player to write out the new spell, give it a school and level and components as appropriate, and then have their character work towards developing and perfecting the spell over Downtime. It's more work, and completely different from what you were describing in the first post...but it would be a more stable and balanced product when you're done.

Anyway, I'm rambling off-topic. It's a pretty cool idea, just give it some careful attention to balance.

 

[Tales and Chronicles]

Do you remember the weird 11th level feature of the UA Mystic? As an action you gained a bunch of Psi Points and you got to spend them now on as many ''spells'' as you could to essentially create your own super spell.
I think you could re-engineer the feature using slots instead of points (they used the spell points variant anyways).

''Beginning at 11th level, your mastery of psionic energy allows you to push your mind beyond its normal limits. As an action, you gain 9 special psi points that you can spend only on disciplines that require an action or a bonus action to use. You can use all 9 points on one discipline, or you can spread them across multiple disciplines. You can't also spend your normal psi points on these disciplines; you can spend only the special points gained from this feature. When you finish a long rest, you lose any of these special points that you haven't spent.

If more than one of the disciplines you activate with these points require concentration, you can concentrate on all of them. Activating one of them ends any effect you were already concentrating on, and if you begin concentrating on an effect that doesn't use these special points, the disciplines end that you're concentrating on.

At 15th level, the pool of psi points you gain from this feature increases to 11.''

You have one use of this feature, and you regain any expended use of it with a long rest. You gain one additional use of this feature at 13th, 15th, and 17th level.

 

[DEFCON 1]

Whether or not this idea is broken would ultimately come down to which spells got cast together at the time. Some pairings wouldn't be broken at all, some might very well be. And there are too many combinations to be able to really tell which side would be more prominent until you actually found yourself in a game and could see the results.

Speaking personally though... if I was to incorporate an idea such as this, there would be an adjustment to one of the rules that you, @Quickleaf proposed... which is that I would change it to the total spell slot level couldn't exceed the maximum spell level they can cast MINUS 1.

In other words... a character than can normally cast 4th level spells could simulcast a 1st and 2nd, but not two 2nds. To me, this is the payment for getting to cast two spells simultaneously, the loss of one spell slot level in power for the turn. This also means a PC cannot start casting two spells simultaneously until 5th caster level, when they get 3rd level spell slots (and thus can cast two 1sts at the same time.) The way I see it... as this ability is along the same lines of what Haste could do in editions past, gaining the functionality to simulcast at the same level the caster could get the Haste spell would be important. I don't think a lower level caster should be able to simulcast.

 

[DND_Reborn]

What if a spellcaster could cast two spells on their turn, with the caveat that the total spell slot level couldn't exceed the maximum spell level they can cast, that only one of the spells can require concentration, and the maximum damage per round is capped at whichever spell deals more (or any) damage?

Would this be totally broken?

I thought about this a couple years ago, but instead of using two separate slots you had to use a slot equal to them both plus one additional spell level.

Using your examples:

For example, a 3rd level mage might simultaneously cast burning hands (1st level) and faerie fire (1st level), calling it "glitterdust" or "fey hands of true flame."

Would require a 3rd-level slot, not two 1st-level slots. You sum the spell levels and add 1. So, a caster would have to be 5th level, and such a combination would use up one of their 3rd-level slots. Expediency comes at a cost.

Or a 7th level mage might simultaneously cast shatter (2nd level) and mirror image (2nd level), calling it "mirrorburst" or "break the veil."

Would require a 5th-level slot (2nd + 2nd + 1 extra), not two 2nd-levels.

IMO the extra spell level cost balances out (at least somewhat) the benefit of getting two spells off on your turn, also you are sacrificing a potentially more powerful spell for two lesser spells, just for the speed.

Now, I didn't have the maximum damage caveat, but I don't think that would change much.

For example, imagine a caster throwing fireball and lightning bolt. This would require a 7th-level slot (using my 3+3+1 idea), and the maximum damage a each spell can do (without upcasting) is 8d6 or 48 points. Rolling 8d6 + 8d6 for damage has about a 90% of dealing 48 points or more, saving throws not included. Now, not many creatures would likely be hit by both, and saves would be separate.

But, if you compare such a combo to other 7th-level spells, such as delayed blast fireball (which only begins at 12d6, but can potentially do 21d6), finger of death (single target, but much more potential damage), firestorm (slightly lower average but a bit higher AoE), or prismatic spray (slightly less damage, but MUCH larger AoE); I think such a fireball / lightning bolt combo isn't OP really.

Finally, using higher level slots makes this self-limiting IMO.

Would this house rule fit one of D&D 5e's classes better than others?

I think this would fit best with Sorcerer (it could be a metamagic maybe) or Wizard, but you could allow it to any caster and it would be fine.

 

[NotAYakk]

Whether or not this idea is broken would ultimately come down to which spells got cast together at the time. Some pairings wouldn't be broken at all, some might very well be. And there are too many combinations to be able to really tell which side would be more prominent until you actually found yourself in a game and could see the results.

Speaking personally though... if I was to incorporate an idea such as this, there would be an adjustment to one of the rules that you, @Quickleaf proposed... which is that I would change it to the total spell slot level couldn't exceed the maximum spell level they can cast MINUS 1.

In other words... a character than can normally cast 4th level spells could simulcast a 1st and 2nd, but not two 2nds. To me, this is the payment for getting to cast two spells simultaneously, the loss of one spell slot level in power for the turn. This also means a PC cannot start casting two spells simultaneously until 5th caster level, when they get 3rd level spell slots (and thus can cast two 1sts at the same time.) The way I see it... as this ability is along the same lines of what Haste could do in editions past, gaining the functionality to simulcast at the same level the caster could get the Haste spell would be important. I don't think a lower level caster should be able to simulcast.

You get usually at most 2 top level spell slots, and 2-3 of your 2nd from the top.

The idea that this is your baseline level of power means ... every turn comes from a 4 round adventuring day?

This isn't baseline power -- this is a description of top power output of a spell caster. By design, spellcasters are not supposed to be generating top power output every turn they are in combat, and the number of turns they can do this is highly limited.

As noted above, a combination of 1st and 2nd level spells is stronger than a 3rd level spell often. Even something as prosaic as Hideous Laughter + Blindness is a double save-or-suck spell, which no spells up to level 9 provide. A level 6 spell slot that caused someone to have to make 2 saving throws and suck if either failed would be a top-tier spell in 5e, as it is a great way to consume legendary resists or punch through high saves.

So we both extended the length of time a caster can maintain top power output, and boosted their top power output. Which makes casters stronger in short days than they where before. Which is exactly the opposite of what casters need.