The typical Sorcerer will have a bonus 3rd level slot, so it'd be four of them, and they'd deal 9d6 (6 + 3 = 9).
Oops.
But that 6th level Sorcerer would have enough left over 1st and 2nd level slots to additionally Quicken two of those fireballs. So possibly he'd be dealing 18d6 per round, which he shouldn't be able to do.
No he wouldn't, because Quicken has a CL 9 requirement.
Worse is a 5th Wizard casting an Extended rope trick without wasting one of his valuable 3rd level slots. Why is this worse? Because the over-eight-hour rope trick is the earliest trick used by many PCs to stop and rest. This is the other half of the "15 minute work day" -- PCs who not only can blow their wad, they can also stop & rest at will. This allows them to have one fight per day, but it's one fight they are very likely to win, because they are able to expend all of their daily resources on it.
The easy way to fix that is to drop the duration on rope trick (though I must say, we've never used that spell at all, let alone for a party hideout). I
think the intent of that spell was to provide a short-term place to hide, not a long-term campsite - that's the way I'd interpret it, anyway, since the "real" camping spells (Leomund's tiny hut/shelter) are 3rd level and up.
Just as bad is a 7th level Cleric using up all his low-level slots to cast Persistent divine power, divine favor, and maybe one other buff of his choice.
You get the idea.
Yeah. Let's not bring in non-core material for the time being, though - I want to balance this against the core rules, not stuff from the Book of Exalted Brokenness.
In Psionics, there's a thing called the meta-cap. It states: you cannot spend more power points on a single power than your manifester level.
I'm not too familiar with psionics, but I've heard of the metacap. Is there a way to apply that to magic? I thought about suggesting you couldn't cast any spell whose level + modifier is greater than your caster level, but that still allows sorcerers to blow off empowered fireballs.
I'd be willing to playtest this idea as a DM or as a player, but I think a couple of the details are bad ideas. Prep casters should have to prep their "metamagic fuel slots" ahead of time as usual and spontaneous casters should NOT be allowed to substitute hp or skill checks for spell slots.
Prepping "fuel slots" is basically the same as prepping metamagicked spells - fiddly and time intensive. Do they still get to use those slots if they're not used for metamagic? I'd appreciate some testing, though, if you're willing.
I agree, sorcerers dumping hit points is a bad idea, now that Nifft has pointed out the flaws in my idea.
