yeah.... 30 is a bit much. especially considering the fact that the resistance it gives you is no longer as high as it used to be(140% resistance as opposed to the original 200%).
To be fair though, for late/end-game players specifically, even 140% is an insane tool. It's not unreasonable to hit 46 All resistance at the max level if you want (Even more with DC and/or rares). At that point, you're taking at most 54% damage. With Shroud, that turns into you being usually completely impervious to damage while healing 86%.
Specialization can actually take that further too, but let's leave that aside and think about what that actually means.
Fear Ward has a really low cooldown. So you can basically go Fear Ward twice (6 turns of ~20% damage, more or less), Dark Intent (-35% boost for 5 turns), followed by Shroud of the Undead (3 turns of healing 86% damage). So let's put this into action. I'll take the All resistance into account too, mind.
On the 6 turns of Fear Ward, you're taking ~10% damage per turn, not including Crits. On the 4 turns of Dark Intent (Since Ward is better, and Intent overlaps with the second use), you're taking 35% of the damage.
So, while you're waiting for Shroud, you'd take somewhere around 200% damage. You then Shroud, and proceed to heal 86% for 3 turns. That's 256%. And then you cycle through it again. You should be able to even take one turn of Crits through Fear Ward there and be fine. And of course, that's not even everything Necro has. It has a small heal, and a stun to accompany it.
When it's put into words like these, it kinda shows how ridiculous Shroud really is. However, I'm not sure about the WAY it's being nerfed. It's way less ridiculous for lower level players, and this puts a definite nerf on that as well.