At great risk of ridicule for my first post, I'll throw this open as a central forum for suggestions for changes/updates to augment crystals... and start with this.
In perusing the lists of currently-available augment crystals, I see a glaring omission: nothing related to spell resistance.
Therefore, I propose the creation of a Yellow Augment Crystal of Rampart. Provides something in the neighborhood of +25 to +30 spell resistance.
I would also have suggested a Yellow Augment Crystal of Leaping... except there are circumstances in which you'd actually want to _not_ have a +40 jump ability (i.e., the High Jump power-up in cannith challenges is sooooo annoying). As one who has done over 1000 challenge runs, it feels like I have wasted a token whenever that ability shows up.