Magic damage was set to give very low points return due to being able to aga all the mobs/roots at once.

It's possible that to 'fix' this, there is now a set # of points per nuke, irrelevant of how much damage or how many mobs you hit with it. Therefore, T1 nuke spam is the way ahead. Not to mention that when using big nukes, a DD might have killed the mob(s) before your nuke even goes off.