D&D 5E Casters should go back to being interruptable like they used to be.

[Shiroiken]

I think some form of this could improve the game.

I would start by having any spell cast as an Action (not reaction or bonus action) trigger an opportunity attack. If this opportunity attack is successful, you must also make a Constitution Save DC: 10 + the spell's level, with a failure cancelling the action (no slot expended). Finally, certain sub-classes (War domain, Bladesinger, Eldritch Knight, etc.) would gain the ability to automatically pass the save, but still have to risk damage from the opportunity attack.

I think this works a bit better than the concentration rules, since the more powerful the spell, the harder it is to successfully cast it. It also keeps reactions and bonus action spells viable in melee, when they're most useful. Certain archetypes shouldn't be punished, however, so they should be able to bypass or mitigate it somewhat.

 

[billd91]

Thanks for pointing that out. Does that mean that they can't be used to interrupt another caster?

Counterspell can, but that just means it takes a caster (of a particular subset of casters) to disrupt a caster. A martial caster can’t do it. They can’t even really do that with mage slayer, and that actually gives them an attack as a reaction to a spell being cast!
Spellcasters probably should have get over some kind of bar to cast, particularly when adjacent to an enemy. Hell, if an archer has to face disadvantage when shooting adjacent to an enemy, a caster should certainly face some kind of challenge. I’m thinking a concentration check might suffice.

 

[Shardstone]

I think it'd be more interesting if the spell is still cast, but is weakened somehow, such as the DC being lowered if the caster takes damage from certain Reactions, or a spell attack roll does does only 2 damage per dice. This makes it so the magic still happens and there's a chance to still cast, but makes it unlikely and adds counterplay. Adjust as needed.

 

[ECMO3]

I think some form of this could improve the game.

I would start by having any spell cast as an Action (not reaction or bonus action) trigger an opportunity attack. If this opportunity attack is successful, you must also make a Constitution Save DC: 10 + the spell's level, with a failure cancelling the action (no slot expended). Finally, certain sub-classes (War domain, Bladesinger, Eldritch Knight, etc.) would gain the ability to automatically pass the save, but still have to risk damage from the opportunity attack.

I think this works a bit better than the concentration rules, since the more powerful the spell, the harder it is to successfully cast it. It also keeps reactions and bonus action spells viable in melee, when they're most useful. Certain archetypes shouldn't be punished, however, so they should be able to bypass or mitigate it somewhat.

This would dramatically change the game. It would make spells in melee combat, even combat spells intended for melee, like Haste, Blur, Mage Armor and Spirit Guardians much more difficult to cast and less useful.

Also this would undoubtedly lead to gimicks and it would make it more difficult to penalize people for moving in combat (do I use my reaction to take an AOO now or wait until this other guy casts a spell).

Note the Mage Slayer feat already does part of this, allowing you to make an attack against anyone that casts a spell within 5 feet of you.

 

[billd91]

Certain archetypes shouldn't be punished, however, so they should be able to bypass or mitigate it somewhat.

Like the bladesinger’s +Int bonus being added to their concentration checks, for example?

 

[billd91]

This would dramatically change the game. It would make spells in melee combat, even combat spells intended for melee, like Haste, Blur, Mage Armor and Spirit Guardians much more difficult to cast and less useful.

Or just require the caster to be more judicious when casting the spell such as casting before entering an enemy’s reach or leaving the enemy’s reach first.

 

[Muso]

Why? How would this improve the game?

In principle it makes the game more tactical. You have.to protect casters in order to have them cast a spell without being in danger to lose it. It depends on how you want to play.

 

[W'rkncacnter]

Start with giving Martials/Non-Casters, a 'I slap that spell out of their mouth' reaction that acts as a melee range counterspell.

"Man, shut yo bi--"
nah but really, making spellcasting trigger attacks of opportunity and letting those attacks of opportunity force concentration checks could be nice. you could make offensive touch spells an exception to that just so they're still usable.

 

[haakon1]

In the older days of dnd, … the rules for a spellcaster, making it so you had to declare spellcasting at the beginning of the round and it was cast when your turn would come up(it was side based and initative would change every round.), and if you were hit, you lost the spell. ….

But come 3e Wizards kinda removed all of this for the most part …

I feel this should return, casting being interruptable in some form,

What do you think?

TLDR: Casters should go back to being interruptable like they used to be …

In 3x, casters ARE interruptible. It happens often.

If someone has higher initiative (or waits for the next round), they can READY an action, most often missile attacks. If they hit, the caster needs to do a Concentration skill check (essentially a Constitution save can be buffed with Skill Points) or lose the spell - the spell is not cast and the slot is lost.

I don’t remember seeing that in other editions, whether AD&D (before 3e) or later editions. Maybe I just didn’t notice folks doing that In 1/2 & 4e. To my memory, 3e/3.5e is the only edition that explicit called for the approach you say it killed.

It does (I still DM 3.5e) have the effects folks are saying. Fighters need to protect casters, especially unarmored arcane casters, and it is like infantry + artillery, or the linemen and the quarterback.

 

[haakon1]

Or just require the caster to be more judicious when casting the spell such as casting before entering an enemy’s reach or leaving the enemy’s reach first.

Just how it’s done in 3x. Getting the first shot off with high initiative is also very important.