For arguments sake am going to call it a book, to me spell crafting should be learned and so scattered pages of 1 seems fitting, could be tomes/tablets/whatever you like.
Get rid of cp entirely, use the hyped spell crafting as a replacement, having to find/ be rewarded with, offensive pages, defensive pages, restorative pages, finding a page of a long lost book will buff the base damage/healing of a skill by a certain percent, have them at different raritys,
White, 0.5 %
Green 1%
Blue 1.5%
Purple 2%
Gold 2.5%
Rewarded from pledges,worthy rewards, battleground boxes, vet dungeon clearances,trial clearances,overland mobs, delve bosses, make them a sensible drop rate, as you really would need a lot of them to get each skill on each toon to a decent level, And that's on set bars you never change,(the harder the activity the better the chance of a better rarity.
As to not upset anyone with stupid high cp each 100 points of cp you have will be exchanged for a set amount of each page
Put in a hard cap on how high you can buff a spell % ( although seeing a dk get his whip up to %300 and just walking around cyrodil just 1 whipping everything would be a sight to see)
Put in elemental pages but these would be rarer and given on weekly leaderboard positions,veteran trial hardmode clearences,(rare chance on hardmode dlc dungeon clearences)
leave magic based damage and physical damage alone and unchangeable (choosable by morph only) so essentially you can make your self, liquid fire, shock whip, blockade of poison, shocking talons,diseased meteor, a frozen volcanic rune, you get the picture. But jabs for example will be physical or magic depending on the morph you take.
Theory crafting community would lose their *** with the possibilitys, meta chasers would lose their golden goose as each toon would have to be customized and buffed to your playstyle and yours alone.really enforcing the play your own way, rather then copy and pastes from YouTube,
Changing the element will keep the damage accrued on the spell, so for instance you could have
A poison whip @ 15%
A shock whip @ 32%
A flame whip @ 50%
A frost whip @ 0%
A disease whip @ 12%
All simultaneously , but for the love of god don't put this behind a p2w by putting pages in the damn crown store,