Not all things are created equal, a tacit fact that is again and again reinforced by the mechanics of Dungeons & Dragons. The fighter can never hope to keep up with the wizard as levels ramp up, and everything a monk can do a swordsage can do better. Even in less fundamental aspects of the game, this can creep in: just ask any melee character who has tried to use a sword and shield versus a two-handed weapon. Indeed, even something as seemingly flavourful as energy types suffer from this. Don't believe me? Compare how many monsters resist sonic damage versus those that resist fire.
At the top of this pyramid of supremacy, force damage is the way and the path. Essentially nothing resists or is immune to force damage, asides from the (very epic-level) force dragon. A few spells and items make a particular call-out for magic missile spells. Next there is the second-tier of energy types: unusual call-outs like holy damage (a la flame strike,) and desiccation damage (a la desiccate.) Very rarely are these going to be resisted or affected in any way: they're virtually "typeless" the way force damage often is. That said, they're also very uncommon. Third tier belongs to sonic damage, which is the most effective of the "core" energy types. Fourth tier holds acid and electricity, in that order, and the bottom tier holds cold damage and lastly fire.
This hierarchy is in no way official or rigid: it's just a vague guideline I've determined from observation. It simply means that putting aside the setting, environment or pre-established foes, if you prepare an acid spell instead of an otherwise-identical fire spell, you're less likely to run across a foe who will be resistant or immune to it. 3d6 acid damage isn't "better" than 3d6 fire damage, there have just been more creatures with fire resistance that have been printed. Demons, devils, dragons, celestials: all the major players shrug off the effects of fire.
So why the imbalance? Is this just another matter of "X is better than Y, get over it"? Well... sort of. The thing is, the greater reliability of the higher-tier energy types often comes with an arbitrary balancing factor. This is perhaps best demonstrated in the orb of X line of spells. Orb of fire deals 1d6 fire damage per level (maximum 15d6) and makes the target save against dazing. Each orb has a different riding effect, though, so the orbs with a slightly better damage have slightly worse effects. For instance, orb of cold forces a save against blinding (not as impressive) and orb of acid a save against being sickened (a comparatively minor hindrance indeed.) Then you get to orb of sound, which can deafen the target (ho-hum) and deals only 1d4 damage per level. The fact it's dealing sonic damage is reason enough to lower the damage dice. Then lastly, there's orb of force, which has no secondary effect and tops out at a maximum of 10d6 damage, rather than 15.
So there isn't really an inherent pros-and-cons debate introduced by using force damage over fire damage, say, it's just that in many cases spells and effects will likely be balanced to somewhat favour the "worse" energy types in case-by-case bases. In addition, there are far more feats, class features and items to improve your cold and fire spells (take even a casual glance at Frostburn) than for, say, sonic or desiccation damage. This is an imperfect science, of course, but at least the effort is there.
If we know what energy types are "best" and which are "worst" (yet have the best spells,) what do we do with this knowledge? Well, fire damage may be much-maligned in general for its generally underperforming against a variety of enemies, but its humble status as the lowliest energy type has earned it the most published support. If all of this support material exists mostly to balance it out against the other types, though, why bother? Well, it would suddenly get a lot more impressive (and hey, interesting for roleplaying) if those shortcomings could be easily undone, wouldn't it?
Enter Searing Spell.
This little gem from Sandstorm does something very unusual - it makes your fire spells so supernaturally hot that they ignore all fire resistance and even still do half damage to creatures with fire immunity. What do you want to bet that a fire elemental has never felt what it's like to be burned before? As a nice bonus, a searing spell also does double damage to creatures with the cold subtype - which is on top of the double damage they were already taking from a fire spell. This peace of mind comes at the acceptable cost of a spell slot one level higher.
So now you can fling fire spells around with little worry for targeting restrictions. Sure, Energy Substitution already existed and doesn't even raise the spell's level, but what if you want to stick to fire spells thematically? A pyromaniac shouldn't have to shoot "coldballs" just because he's facing an efreet. More importantly, it's generally the case that if a monster has resistance to one energy type, it does to most of them, especially with Outsiders and at higher levels. It's also the case that changing the energy types of your spells won't let you reliably capitalize on its original energy type - something that can be very handy, as we're about to see.
So removing the biggest downside of fire damage is a real coup, but pumping the cost of all of your spells by one level is a pretty hefty cost. Is there enough support for fire damage that can make it worthwhile? Unshockingly, the answer is... perhaps!
