Am I right if I assume you would not allow lets say a 7th level spell that is as fireball but with a casting time of a free action. I wouldn't understand these spells are already out there.
1st Featherfall, a quickened 1st lvl spell, that can be cast even out of your turn
Call it personal bias, but I think there's a difference between a purely defensive spell like feather fall and a quickened fireball. I'd always allow more leeway for defensive spells than for offensive ones. Featherfall just prevents fall from damaging the caster, not really the realm of powergaming. There shouldn't be a need for a wizard to be able to cast contingency to do that much...
2nd Scincilating Sphere [MoF], a 3rd lvl spell same as fireball but lightning damage, energy substitution already applied
Yeah, one of the most boring designs ever. I mean, from the pure damage aspects there's no difference between Fireball and Lightning Bolt, too. But at least they have a different appearance/area of effect, even though the Bolt lost it's rebound ability...
But yeah, Energy Substitution is probably the easiest feat to justify. After all, there are "Orbs" for everything... And why should your great race of arctic elves all learn fireballs and then substitute it, instead of learning ice balls straight away?
3rd Delay Blast Fireball, higher damage cap than fireball, but there is a metamagic feat called Delay Spell
...maybe there are more, maybe not
Higher damage cap is different from, let's say 1.5 x caster level, I haven't seen the latter in a normal spell yet. Personally, I think a fireball with a little bit more damage and an added delay effect is different enough from a normal fireball to justify a spell of its own. And don't forget that it existed way before anyone thought about metamagic feats
So why disallow such spells too be created, if they are already out there and no one bothers?
I'd disagree that there are that many out there who completely mirror metamagiced spells. Mostly they add their own twist to the mix. Which is just the grain of sand they need to be justified. Magic spells should have a mythic element, not just be plainly built from formulas. (cf. free-form magic systems)
Some metamagic feats are worse than others. Energy substitution borders on the actually usable, though I still think for electricity a line is more evocative than a ball, for fire it's the other way round...
But even quickened spells could be justified, with some additional flavor. What about "Ottos Orbiting Orb of Obliteration", which creates a ball of fire circling around your head and can be commanded to seek a target as a free action? Not quite as powerful as quicken (probably duration 1/minute/level + able to dispel it), but at least it has some of it's blandness removed.
And yeah, we're really getting off-topic. Of course, you could (limited) wish for one of those spells to appear in your spell book, couldn't you?
