I just threw together this example image from a screenshot.
My suggestion is simply that it might help players if something like this exist in-game:
NOTE: The spells that have no "defense icon" in their top-left corner, either is a buff/summon or always hits.
The purpose of this chart is to helps me decide for instance:
Get a better understanding of the limitations of the Wizard specialization choices.
What are you opting out of when you pick a certain school? I found it was very difficult to determining which spells you loose at glance. After looking below I feel like I could live without Enchanting and Conjuration. That is great there is a school that gives up just those two, Illutionist. Oh, but wait. Illusion doesn't have a 7th or 9th level spell. So, that was what Josh was referring to in one of the update videos.
Not all summoned weapons target deflection, perhaps my Battle Mage should pick up both staves.
What spells should I pick at level up? Should I pick the 2nd level spell that causes blind when you already have the 1st level spell Chill Fog. Oh, one targets the opponent's Fortitude while the other targets Will.
What do you all say, wouldn't you like to see similar tool in game, or are you all making your own spread sheets, or keep it all in your head?
(In the future I might throw together something similar to all the Grimoires and what they cover in the tree, so you can make a Wizard multi-class that relies less on spells picked up during the level-up screen and thus leaves more room for abilities the other class.)