Skills are not gear.
By allowing skillbooks to be random for such a limited selection of skills, it doesn't improve gameplay but detracts from it. If you create a character with the intention of being a fire mage - and suddenly find you cannot ever find fire elemental, you're incredibly weak (but playable).
If you plan the same character as a lightning mage but cannot obtain blitz bolt... you're useless.
The random attitude of vendors concerning skillbooks is a poor one simply because there are only what, 4 spells per level? So it's not like a DnD Wizard who cannot learn fireball because he'd have acid splash, lightning bolt and cone of cold (sure, CoC is level 4 not 3 but you get the point). This game's spell list does not create alternatives within a specific tree. Without key spells you are so weak you're unable to play what you intended to.
Were there more skills per level, with choices (imagine if there were 3 1 turn cd fire spells spread between levels 1 and 4 giving options... you'd only need to find 1 of them).
So yeah, I can agree it'd be nice to have some random skill find, except skills are not treasure... skills are no different to talent points. Being unable to choose them is not fun, regardless of whether it's fun to discover them in the world.
Do you know there are only that many skills per level or is that something that people are assuming based on incomplete spell lists. Not a single person has claimed to have data mined spells.
Why aren't skills treasure? Everything is treasure. They utilize AP to accomplish goals exactly like special arrow types for an archer character. You choose your basic attack types at the beginning (Presumably you chose one without a cooldown to have a repeat ability similar to a basic attack) and you have a staff ranged attack to fall back on. Then you acquire them like treasure.
It's not fun to you. I disagree in that it's fun for me to discover them in the world as an emergent narrative. It's easier for you to manipulate the game to have all the spells than it is for me to replicate random acquisition. That's the goal...to allow for those who enjoy an unscripted experience to not be forced into going to the vendor and saying 'oh...that's all my spells I'm going to get for the next 25 hours of gameplay....fun?'
