Are these feats from Blood and Treasure usable as proficiencies?

Okay, so I cheated on Autarch recently-- sorry, boys-- and bought Blood and Treasure on some trusted recommendations. Now there were bits of it I liked and bits of it I didn’t (Mainly, the 3.5-isms like huge spell and monster lists, and Bards, Rangers, and Assassins casting spells). One of the parts I really liked was its feats. Trim but robust, if I didn’t like the Proficiencies in ACKS it might be my go-to in the future.

My question is this: How viable would it be to turn a couple of the feats in it, which I thought were an interestingly simplified take on the idea, into special proficiencies for characters capable of casting spells in ACKS (and one as a general proficiency)?

For those of you that don’t have B&T, here are the feats I’m interested in porting over reproduced (Most of the book is Open Game Content, and even if it weren’t I think this qualifies as fair use):

Empower Spell: You can cast one spell per day with all of its variables
doubled (i.e. instead of 1d6 points of damage, it deals 2d6 points of
damage, or instead of the effect lasting 1d4 rounds, it lasts 2d4 rounds.

Enlarge Spell: You may double the range of one spell that you cast
each day.

Extend Spell: You can cast one spell per day with double the normal

Silent Spell: You can cast one spell per day without vocalizing it.

Still Spell: You can cast one spell per day without moving your hands.

Widen Spell: Once per day, you can double the area of effect of a spell.

This last one is the one I was thinking of as a general proficiency.

Magical Aptitude: You learn to cast a single 0‐level magic‐user spell
once per day. You may choose this feat more than once, applying it to a
different 0‐level spell each time. Any character can take this feat, even
magic‐users. (Note: I’d probably have to make this first-level spells, of course, since ACKS doesn’t normally use cantrips)

Would this mess up balance terribly, require too much translation, or even just be stupid?

I would be concerned about a lot of those. If you look at the effects of a lot of the proficiencies in ACKS, they typically have effects in the 5% range (e.g +1 to hit). Consider the results of being able to double a spell like Sleep or Fireball; why wouldn’t every spellcaster take one or several of these over the course of their career? Even the last one…at first I thought it was a bit more harmless, but on further consideration it’s like partial multi-classing as a spellcaster, but with none of the downsides. Once again, consider the character that selects (or rolls, if it’s random) Sleep as their spell. As soon as something becomes an obvious choice over other options, there’s a problem.

No worries about your “adultery”, LL :wink: Blood and Treasure is a fine game; I bought it too. I think we should all buy as many OSR products as we can.

Whether or not to use these proficiencies is a tough call. Some of them are rather more powerful than related proficiencies in ACKS.

The way I usually think about balance is to consider “what would happen if a gave a villain these proficiencies”?

Empower Spell: A villain with a sleep spell would wipe out an entire low-level party. A villain with a fireball would wipe out an entire mid-level party. I’d disallow.

Enlarge Spell: A villain with this proficiency could do a long-range ambush with a fireball or lightning bolt, or an illusion or summoning from a great distance. This would be interesting and not game breaking. Probably fine.

Extend Spell: Given the length of most ACKS buffs, and the ease of dispel magic in ACKS, this proficiency would not be overly powerful. Probably fine.

Silent Spell/Still Spell: This proficiency is probably not even as useful as the existing Quiet Magic. I’d combine them into one.

Widen Spell: Using the rules in Player’s Companion, spell area-of-effect is easily traded-off against spell damage. This proficiency has de facto the same implications as Empower Spell. It also could be unbalancing in mass combat. I’d disallow.

Magical Aptitude: I would definitely NOT permit this as a General Proficiency. Why would you take Craft or Labor when you could take this? You wouldn’t.