This is one way I think that Fable 2 could do things better
Taking the concept of increased power for evil spells if your evil and good spells if your good to the point that the spells that are in line with your morality be exponentially better the more pure you are in that morality
Something like this perhaps
For spells that are in accordance with you morality, power would increase as such. The increase at the highest levels is so great it would require that the starting levels be fairly low.
- +10%
- +20%
- +40%
- +80%
- +160%
- +320%
- +640%
- +1280%
- +2560%
- +5120%
For spells that are opposing your morality effectiveness would decrease this could be a decrease in casting speed, power as well as an increase in the chance that the spell will fail all together. Take the positive of these values for that one.
- -10%
- -20%
- -30%
- -40%
- -50%
- -60%
- -70%
- -80%
- -90%
- -100%
This system would push you to strive for extreme or the other. Neutral players would have the benefits of both sets of spells but a cost of the true power that the spells are capable.
It would be also nice if there were Hero level NPCs that used spells as well with the similar morality NPC befriending you and the opposing morality attacking you. The idea that prompts the desire for magical wielding NPCs is that there could be evil spell that offset good spells and vice versa. One example of this could be disable Physical Shield as an evil spell. Another example could be Tranquility which would counter Berzerk.
On the other hand I hate having a spell that is only good against one boss on one very small part of the game. So perhaps this could be a single spell that summons great evil or great good to aid you and your allies or hurt the enemy. It could work in a similar way to Infernal Wrath or Divine Fury but would basically aid or hurt those within it's area of affect depending on there morality. This spell would have no effect on neutral creatures. Of course the power of this spell would depend even more on the morality of the caster to the extent that you could only have one of the two spells and it would manifest once you reached a certain strength morality and disappear should you fall below that level.