Let's set aside the enormous amount of effort that would go into designing, coding, and testing this feature.
This will not happen out of consideration to the players. Blades of Avernum is a complicated game. It takes time to learn what all the skills and spells do. I do not want the player to have the rug pulled out from under him or her and have to learn a new game every time he or she starts a new scenario.
In addition, players will be able to specialize in certain spells in Blades of Avernum. If a player spends a lot of effort bringing a certain spell or skill up, I do not want that player to suddenly be unable to use that skill. I don't want someone who relies on Lightning Spray to start a new scenario and find that Lightning Spray has been changed to Summon Jellybeans, and the character specialized in spear can't hit anything anymore because the Pole Weapons skill is now useless because the characters in the new world don't use spears. And I don't want Unlock Doors to stop working altogether because the designer didn't want to design a scenario that could handle it.
We're the designers. That means, to be responsible, we have to design for our players _in_good_faith_. Those spells and skills are the tools I have given the players to play against your creations. Some things would be gained by allowing this freedom, but something very important would be lost too.
