Elemental wand penalty

I believe at some point Neckson introduced the damage penalty for mages using the wrong element. I feel that it makes so much sense and should be implemented here as well.
E.g.
- Fire/poison attacks should get a reduction from wands 7/8
- Ice/lightning attacks should get a reduction from wands 5/6
- Holy attacks should be reduced by all elemental wands
- Neutral attacks like mclaw/bigbang should be unaffected

Perhaps we could then have some wand diversity and some utility for actual luk mage wands since they would be better for bishops. Thoughts?