Skills and spells have a meaning
In Planescape, one of the cool things that really added to the story was that most skills, spells and magical objects had a reason, a significance in the story.
You knew how you had obtained that particular skill and why, it wasn't just something you picked in a tree because you had levelled., it was something you had acquired during a particular event, a truth learned, a better understanding of the universe achieved, and usually you had paid the price in pain or learning for it.
For example you didn't find random ring+1 or standard fireball spell, the spells you could learn by understanding the circle of zertimon, by being taught the power of fire by ignus, even more "standard" spells could be obtained fior instance by studying the workings of the wards of giant undead skelletons... Objects were remnants of a previous life, tokens obtained after talking to strange being related to that particular discussion, You had tatoos that related your experiences in the game and that experience gave it power.
This kind of attachement of equipment/skills to the narrative is a great addition to the world and the involvement. In the end the spell of the rune of torment was the summum of that logic and it is what made that spell not only a high level powerful spell but really something you could understant the workings of and the reason for its power. It participated to the emotional link to your character.
I hope that this way of dealing with skills spells and equipement will be given all the attention it deserves in the game.
Great idea, i really think this should be implemented, it's really one of those things that made PST stand out.
Arsene Lupin commented
I kind of think the game needs both. More generic abilities that are everywhere, and common... and more unique abilities that have narrative significance and meaning. (The Slayer transformation in BG2 would be a great example of this, as would the "raise dead" spell in Planescape Torment).
Beyond that, I think I'd like to see MORE spells arising naturally through interaction. So, for example, if you see a mage casting a fireball spell, you could learn how to use that spell by studying his movements and motions (or you could just by a scroll in a shop). That way, players chould choose to learn generic spells either artificially (buy spell, add to spell book, memorize) -OR- do so naturally (examine enchantment on locked door, learn spell that locks doors, etc.).