Supposedly at Lvl 70 you need 40 resilence to reduce the crit rate by 1% and 20 resilence to reduce crit damage by 1% which sounds reasonably based off other known numbers. Though it seems potentially rated a little too low. The reason I say this is due to Magic Spells that are untalented do 50% more damage when they crit which means you only need ~33.3% reduction of crit damage to get them to be in the range of noncrit damage. So 33.3% * 20 = 666 Resilence which with sockets seems to be an almost achievable number and definately potentially possible by the end of expansion if gears improves at all similarly in the expansion as it did in the original game.
I'm partially not sure how defense is supposed to compete with that unless resilence gets a different mechanic in PvE.