afaik ring of frost and shadowfury are 30 sec cd, disrupting shout 45 sec (
http://us.battle.net/wow/en/game/mis...t-calculator#e!) although I'm not sure if those numbers are still accurate I'm not up to date regarding the beta, I know most of them share dr but since the cooldown is that low it doesnt really matter because everything is ready again once dr is resetted
and so far grounding doesnt absorb aoe effects
And I'm not sure if blizz is going to change that as its logical to implement more aoe cc because of RBG