Keep the old sigil drops with additional effects, if you dont do so, people wont find corp worthwhile to kill, since it is 2007 and the gear is limited and corp would be hard to kill and not rewarding.
You might want to tweak the effects down a few percentages for the divine, elysian and arcane to about
Divine - Reduces damage by 20% + original prayer point drainage
Elysian - reduces damage by 15%, 50-60% of the time
Arcane - Cut +20 mage bonus into +15
25-Jul-2014 19:57:24