This is something a couple of us have been talking about over at ENWorld for a while now. The idea of the concentration slot - it's something of an adaptation of the limited buffs rule, but more general.
Note that if inplemented this would be a BIG change to how the game plays, though it wouldn't necessarily have any back-compatibility problems...
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First rough outline of a concentration slot system.
Number of concentration slots = caster level + 3. (As a starting point - I haven't really crunched the maths but I think this may be too generous at high levels. Perhaps 2/3 caster level + 3 might be a bit better)
A spell generally requires a number of concentration slots equal to its level divided by 3: 1st-3rd level spells require 1 slot, 4th-6th level spells require 2, 7th-9th level spells need 3. A spell must have concentration slots devoted to it over its entire duration. To cast an instantaneous spell, the caster must have enough empty concentration slots at the time of casting. Increases to spell level due to metamagic etc increase the number of slots required proportionally. So a quickened maximised scorching ray would require 3 slots. Spells that currently have a 'concentration' duration require double the normal slots. Cantrips do not require concentration.
(Alternative: casters get caster level + 3 concentration slots, and spells require level/2 slots to be cast. Again, I'd like to emphasise I haven't done the maths on this one...)
Assigning a concentration slot is a free action performed as an integral part of spellcasting. Reclaiming concentration slots happens automatically once a spell is dismissed, dispelled or has its duration expire.
Some spells are much more demanding, and require more concentration slots. This is a balancing issue, and should be used to shape play. I would personally put teleportation spells into this category. This would nerf buff-scry-teleport tactics to come degree, since the concentration slots required to perform the teleport would limit available buffs. Combat spells that use ridiculously expensive material components as a balancing factor would also be a candidate here (hi, Forcecage...), although we're still stuck with expensive material components in non-combat spells like Raise Dead, since in the situations when these are cast, concentration is less likely to be an issue.
Other possible uses for concentration slots:
- as a free action, can devote a free concentration slot to give a +2 bonus on dispel checks, either to dispel an enemy's spell or to prevent the dispelling of one of your own.
- as a free action, devote a free concentration slot to give a +2 bonus on Concentration checks to avoid fizzling a spell due to distraction (taking damage mid-casting or environmental conditions etc).
- perhaps some way of using concentration slots for the purposes of counterspelling? Shouldn't steal the thunder of Dispel Magic from the abjuration specialists, but allowing some measure of spontaneous counterspelling from all casters can only help increase the 'mageduel' feel that D&D has never done well. And making counterspelling easier and more accessible can only reduce the power of casters in general, and so improve things for non-casters at high level.
This system would also allow the restructuring of save-or-die spells from their 3.xe swinginess or their Pathfinder just-another-way-of-losing-hit-points-iness. Save or die spells would now come into effect at the end of a duration - perhaps three rounds for the lower level ones (Slay Living), or one for the higher level ones (Implosion, Destruction). The caster has to maintain concentration on the spell for the entirety of this duration, or it has no effect. This gives the target the chance to ward himself against the spell effect somehow, get the hell out of range, kill/distract the caster, compel the caster to drop the spell in order to deal with tactical developments elsewhere, etc, etc. There may be penalties accruing over the course of the spell, or there may not be - depends on the individual spell.
Of course there's scope for all sorts of new feats/spells, just like there is every time you introduce a new subsystem. Feats to get new concentration slots, or let your familar contribute. Debuff spells that tie up a casters concentration slots or make their spells more draining to maintain. Etc etc. Perhaps antimagic could be reworked to make spells *hard* to cast rather than completely impossible? Depending on the caster level of the antimagic effect, all spells could require X more concentration slots than usual, which would mess up low-level casters completely and limit high-level casters to their lesser spells.
General goal here is to limit uberbuffing as a viable tactic, and make casters less nova and more measured (thus making combat last longer and giving non-casters more chance to shine at high levels). Also to force more choices - sure you can make the whole party flying and invisible, but is it really worth tying up all that concentration and limiting your offensive capacity? Caster can still teleport in and go boom, but he's going to be a fair bit more circumspect since he'll have fewer buffs up, and be a lot more vulnerable if his big metamagicked boom doesn't do the job first time. Also, making counterspelling, dispelling etc a bigger part of the game.
Big area i'm leaving uncovered here is what to do about creatures with spell-like abilities. Do they need concentration slots, if so, how many and how are they balanced? Needs thought...
This is something a couple of us have been talking about over at ENWorld for a while now. The idea of the concentration slot - it's something of an adaptation of the limited buffs rule, but more general.
(stuff...)
If I get your idea right, a spellcaster could only have a certain number of "levels" of effects at any due time, and could not cast instantaneous effects if the caster's "concentration" is saturated?
The idea is good, but the number of concentration slots available and usage of those concentration slots appear unintuitive at the moment.
If you could re-write a more concise and clearer description, perhaps with an example, it would be easier for us (for me at any case) to grasp your concept and comment.
This would be worth doing, as is sounds like a good concept.
'findel
At any case, I like the fact that the buff limit is coming from the caster rather than its recipient(s).
may have a simple solution,
bonus spells from high ability are those conc slots
or are how many you get where
no need to assign a value then, it's the spell level
or assign a rating, and conc pool = sum of bonus spell levels
If I get your idea right, a spellcaster could only have a certain number of "levels" of effects at any due time, and could not cast instantaneous effects if the caster's "concentration" is saturated?
The idea is good, but the number of concentration slots available and usage of those concentration slots appear unintuitive at the moment.
If you could re-write a more concise and clearer description, perhaps with an example, it would be easier for us (for me at any case) to grasp your concept and comment.
This would be worth doing, as is sounds like a good concept.
'findel
Ok, trying to neaten it up/formalise it a bit...
CONCENTRATION
The number of spells that a spellcaster may have active at any moment in time is limited by the number of concentration slots he has available. A spellcaster has a number of concentration slots equal to 2/3 his caster level + 3.
The number of concentration slots required by a spell depends on the spell level. A spell of 1st to 3rd level requires 1 concentration slot; a spell of 4th to 6th level requires 2 concentration slots; and a spell of 7th to 9th level requires 3 concentration slots. The number of slots required by metamagicked spells is calculated using the spell level after the metamagic adjustment is applied, so for example a maximised magic missile spell (a 1st level spell with a +3 level metamagic feat applied) would occupy a 4th level spell slot, and therefore require two concentration slots.
- A spell with a duration of 'instantaneous' or 'permanent' requires that the caster have sufficent unused concentration slots available at the time of casting.
- A spell with a duration in rounds, minutes, or hours requires that the caster devote sufficient concentration slots to the spell for the entire spell duration or until the spell is dismissed or dispelled.
Exceptions to the regular concentration slot requirements are as follows:
- spells whose duration includes the word 'concentration' require double the normal number of concentration slots, but concentrating on a spells is now a move action rather than a standard action.
- conjuration (teleportation) spells require one additional slot for every additional character that travels along with the caster.
If a caster has insufficient concentration slots available to meet the requirements of a spell, he may not cast the spell. When a spell ends, is dismissed, or is dispelled, the caster immediately regains all concentration slots that it was using.
DISPELLING
A caster using dispel magic or greater dispel magic can decide to 'boost' the dispel by devoting additional concentration slots to it. Each additional concentration slot used in this way adds a +2 bonus to the caster level check. If the caster of the target spell is aware of the dispel attempt, he can 'reinforce' his spell with concentration slots. This is not an action and can be done freely out of the normal initiative order. Each concentration slot used in this way increases the target number of the caster level check by 2. Concentration slots used to reinforce a spell are regained at the start of the caster's next turn.
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Ok, that's a basic summary. I'd still try to include some sort of spontaneous dispelling mechanism using only concentration slots, but that's probably a bit advanced for now - would like to get some feedback on what I have before getting into the advanced class.
Also bear in mind that the number of concentration slots is a 'by eye' choice, and is completely untested.
Also, from the original post but included here in the interests of completeness, and because I think it's an important side-effect of the system:
This system would also allow the restructuring of save-or-die spells from their 3.xe swinginess or their Pathfinder just-another-way-of-losing-hit-points-iness. Save or die spells would now come into effect at the end of a duration - perhaps three rounds for the lower level ones (Slay Living), or one for the higher level ones (Implosion, Destruction). The caster has to maintain concentration on the spell for the entirety of this duration, or it has no effect. This gives the target the chance to ward himself against the spell effect somehow, get the hell out of range, kill/distract the caster, compel the caster to drop the spell in order to deal with tactical developments elsewhere, etc, etc. There may be penalties accruing over the course of the spell, or there may not be - depends on the individual spell.