Critique this house rule - blank spell slots

[freyar]

The question I have is what constitutes a "spell you are able to cast" for a wizard? They can cast anything in the class list from a scroll, but I doubt you mean that. But do you need to refer to a spellbook? Or just have it in a spellbook back in your home you haven't been to in weeks of adventuring? You could limit it to spells you have applied Spell Mastery to, but that seems less than what you want. As for letting clerics use this, it seems like a big boost to their versatility.

 

[Dannyalcatraz]

That kind of defeats the purpose.

Fair enough.

Maybe I should just limit it to prepared casters, and 1 full round action to swap it out might make it more balancing. And I agree that it does tread pretty heavily on wish/lw at the high levels, but limiting it to 6th level or lower spells seems kind of contrived, IMHO.

Well, while I suggested you not make it a Metamagic feat, if you did make it a Metamagic feat, you could justify that level limit by making it shift the spell's level +1-+3, depending upon how useful & powerful you think this feat is.

As a Metamagic feat, you'd only take it once, since its inherent mechanics make duplication useless.

 

[Herzog]

I'm rather amazed nobody mentioned this feat already exists:

Alacritous Cogitation CM37 You can leave a prepared spell slot open to spontaneously cast a spell.

(NB: from the consolidated list archives
Feat Index

Don't have my books at hand, but as far as I can remember it pretty much does as you describe.

 

[Some_call_me_Tim]

I don't have a clever name for this
Blank spell slots can be prepared without preparation.
Benefit: As a swift action, you can fill a blank spell slot with any spell you know or are able to cast. The spell can not be of a higher level than the slot (though it can be lower). You can only fill one blank spell slot per spell level in this way. This feat can not be taken multiple times.
Normal: Filling a blank spell slot takes 10 minutes per spell level to fill.

I agree its a bit too powerful, even if it is only one spell per level. I like that you are trying to make mages be able to have the right spell at the right time, without having to resort to carrying a boatload of scrolls.

I would at least make it a move action, as they thumb through their spellbook. I would probably make it a standard action and they need to access their spellbook as well. Another thought would be to make it a full round action. This would mean such a spell would basically require two rounds to cast. One to prepare, one to cast. These means it is less useful than a scroll (albeit much cheaper), but more useful than waiting ten minutes in combat.

 

[Megahedron]

Yeah, that's rigged. I wouldn't advise allowing that. If anything, it should be a feat with spell mastery or something similar as a prereq.