Jeff Carlsen
Adventurer
For Vancian casters, I wouldn't mind an option to prepare spells at a higher level slot (not sure how high) which enables multiple uses per day, or simply per encounter, all at the same effects as the lower prepared slot. Perhaps with an option to overcharge it and burn it as a full daily at the actual prepared slot level.
Level 3 Fireball, in appropriate slot does 3d6 damage.
Prepared in a level 6 slot, it has multiple uses, perhaps one per slot level, or is just an encounter spell.
Then if you haven't yet used the spell or another unthought of limiting factor, you can burn it completely for 6d6 damage.
Perhaps this would work similarly for a charm spell, at the higher spell level, you can naturally charm more powerful creatures, or Multiple low level creatures..
I could see something like this. Some spells already have ritual options, so alternative casting mechanisms (essentially metamagic) could be built into certain spells. For example Fireball could have:
Renewable: Prepare this spell as a sixth level spell. This spell is not expended when it is cast, but may not be cast again until the caster spends one minute renewing it.
Infinite: Prepare this spell as a ninth level spell. This spell is not expended when it is cast and may be cast again.
Doing it this way means that the designers can choose which spells get the abilities and what the appropriate level for each ability is.