Energy Substitution and [Force]

[Hedgemage]

I know that normally you can't use Energy Substitution on a spell with the [Force] descriptor, but... what if you could?

Allowing players to substitute force for fire, cold, etc. would be insanely overpowered, but what about substituting the other way around?

Take Magic Missile for example. If it was modified to use fire energy, it would do fire damage, but would lose the perks of force (like affecting incorporeal things), but it would gain the ability to affect objects.
Some things like Mage Armor would also change in a similar way. By being fire instead of force, it wouldn't protect against incorporeal attacks. But, wouldn't gain any benefit from being fire, cold, acid or whatever.

Any reason I shouldn't allow energy substitution to replace force with another descriptor?

 

[paradox42]

In my own game I house-ruled a feat based off of Energy Substitution that lets the caster substitute [Force] in place of [Fire] or any other of the five basic energy types, but requires a spell slot 1 level higher than normal. So a Forceball would be a 4th-level spell, a Cone of Force would be 6th, etc. I haven't had any problems with it, though admittedly the really serious powergamers/optimizers in my play group haven't had a crack at it yet. Spells tend to end up on the slightly powerful side of their new level when they are Force Substituted, but no more so than (for example) Magic Missile itself is compared with other 1st-level spells.

But, given this, I'd say allowing a mage to substitute a basic energy type for Force would not only not be overpowered, but would actually underpower the spell due to the loss of advantages such as those you noted yourself. It might be worth one of those "anti-Metamagic" effects that sometimes gets bandied about, for example Minimize Spell which subtracts 2 levels IIRC. Then again, allowing a cantrip to unleash 5 Flame Missiles (as a 9th-level caster) is probably just a bit too good, so maybe not.

It's a pity one can't add/subtract half-levels.

 

[Hedgemage]

My thoughts exactly. The only benefit of replacing force with another descriptor is that in general, force damage doesn't affect objects.
I suppose you could increase the list of spells that benefit from things that increase effective caster level for one energy type or another, such as a feat or effect that gives +1 level to spells with the [fire] descriptor or some such.

 

[hbarsquared]

I disagree that such a use would be "underpowered." But I do believe that a spellcaster with the feat Energy Substitution casting flame missile instead of magic missile would still be balanced. It still "costs" the use of a feat in order to change a [force] spell to an [energy] spell.

My reasoning is this: the only time one would wish to do such a thing would be to 1) affect objects, or 2) apply 150% damage to an opponent with energy vulnerability.

So, don't look at it from the perspective of "well, I'm losing these benefits of [force]." Look at it from the perspective of, "if one were to substitute [energy] in a particular circumstance, what is actually gained?" The answer is 150% damage.

I think requiring a feat, with no increase in spell level, is appropriate for substituting a [force] spell with an [energy] descriptor to deal extra damage to vulnerable opponents.

 

[Jondor_Battlehammer]

I forget where it is, but there is a Force substitution feat. It turns all damage dice to D4s, but you can hit incopreal creatures with no miss chance.