What if? Spellbooks

Under 3e Rules as Written, when a PC wizard captures a spellbook from an enemy wizard, he is not able to use it right away. Instead, he must first decipher the spell (read magic) then learn the spell (Spellcraft check), then copy the spell into his own book (100gp per page, one page per level, and IIRC one page per day). After which, he must consult his spellbook every day to prepare the spell, and has no further use of the captured book - he can sell it on to recoup his costs.

But what if...?

• The requirements to decipher and learn spells were the same, though spells could only be learned during downtime (between adventures). However, the requirement to copy spells is removed.
• Captured spellbooks were prohibitively expensive to copy - say 1,000gp per page and one month per page, because they must be copied exactly and with lots of rare materials.
• Between adventures, Wizards were assumed to refresh their memory of all their spellbooks. During adventures, he can prepare any spell from any book he owns, without needing to carry his books with them.
• If a Wizard lost a spellbook, and so couldn't refresh his memory of it between adventures, he lost access to the spells it contained, and would then have to relearn them if he acquired a new copy.

Additionally, spells would be split up into three categories: common spells (those in the PHB), uncommon spells (those in the Spell Compendium), and unique spells (everything else, notably the Complete Book of Eldritch Might).

When the Wizard levels up, he is allowed to add four spells to his spellbook (as normal, except it's normally two), but these have to be common spells - chosen from the PHB.

Uncommon spells are those found in rare tomes, but there are multiple copies of them floating around. So, if a Wizard captures a book containing these spells then it's a good find... but there's no guarantee he won't run into another Wizard with the same spell. Additionally, if a Wizard wishes to explicitly research an uncommon spell, he may do so - the nature of the spell is well enough known that dedicated effort can unlock it.

Unique spells are just that - there's only one copy of each of these spells floating around, so if the PC Wizard has it, he can be sure nobody else can match him!

(Under this model, it wouldn't be possible to learn a spell from a scroll. Under strict 3e RAW, this is actually already the case - the strict rule is that scrolls can be used only to aid in spell research. However, I don't think anyone actually uses that rule.)

The effects of all of this should be primarily flavourful, although one key advantage is that the Wizard ceases to be so utterly dependent on his one and only spellbook. In terms of flavour, it means that Wizards have a strong incentive to seek out new spellbooks to find lost and unique spells. It also means that if the Wizard does get his hands on such a book, he doesn't need to spend huge amounts of money adding it to his own book before he can use it.

(I would probably also match this with an adjustment to the starting spellbook - instead of getting all the 0-level spells for free, I'd probably change that to 6+Int mod.)

While I'm on the topic - Clerics and Druids

Of all the classes in the PHB, the Cleric and Druid are both probably the most powerful, the ones that gain most from additional supplements, and also the most difficult to play. The reason for this is simple: they gain access to all the spells on their list, of which there are a huge number. And if you add the Spell Compendium of other books, they automatically gain access to those spells as well.

(The same also applies to Rangers and Paladins, of course, but to a lesser extent.)

Fundamentally, I'm inclined to do the same for Clerics and Druids as I've just done for Wizards - they too must keep a record of their known spells (in a canon for Clerics, or in the form of stone tablets/wood carvings/whatever for Druids). And as they level up they, too, add more spells to their selection, or can learn yet more by capturing holy works from other casters.

(This probably works best in a setting that doesn't have strictly defined gods, or one where one of the underlying mysteries is that the gods are a front - there's no difference between a Cleric of Pelor and one of Vecna because they're both actually tapping into some grand, impersonal source of divine magic.)