A rune with this amount of critical damage rating is not even justified by 100000000000 achievement points. 30% critical damage simply can't be justified in AoC's case where critical rating (and normal damage stats) already is the most important stat for most classes. With a full AA tree, best gear with crit stats you can reach like 30% on some classes, this rune equals basically 6 armor parts + rings + weapons + aa tree talents + feat tree talents, this is completely out of place in terms of balance, regardless in which way you can obtain it.
Some classes are unstoppalbe with this ****ing thing and because of that some other classes will become completely useless. Guards can already have problems against DTs who go for insane damage because of their critical hits and they want to double the critical damage amount?