I'd suggest introducing a mechanism to stop the rotation of the shield to increase it's tactical value. Something like "pay 1 to keep the current shield. Consumes 1-2 per turn till deactivated." deactivation cost could be 0.
For Bone Wall and Dissipation Field, does it revert back to Chaos Buckler when it runs out of bones/quanta to keep going for any longer?
http://elementscommunity.org/forum/index.php/topic,14213.0.html (http://elementscommunity.org/forum/index.php/topic,14213.0.html)