How aboute spice this build a bit by adding an Orb of Annihilation as a secondary skill instead of dream eater? I have craft +49 OoA on necro wand and it works very well in Duncraig and Fauzut. Single target bosses might be a problem, but Singularity from
Runeword Level: 110
+1 to All Skills
+(5 to 10)% Bonus to Spell Focus
10% Hit Recovery
+(15 to 20)% to Physical/Magic Spell Damage
+(12 to 15) to Singularity
(15 to 20)% to Energy
+(150 to 250) to Mana
Physical Resist 5%
+(100 to 200) Life when Struck by an Enemy
can do descent job.
It's a good idea ! OOA always work without any special investement so it's a nice thing to add in general. You don't need to change your set up whatsoever though, so no need to concern over that. (also as sio noted, you probably mixed up Death Ripple and Dream eater but np)
I did a few tests with it, but almost everywhere farming normally with Death Ripple felt better. The only place I did have my fun with ooa was in fauzt, there necrobots tank too much (as death ripple is half phy) and enemies are too spread out, so with a mediocre gear, also using ooa on top of malice skills helped clear better.
You can see me playing it here https://www.youtube.com/watch?v=1PTB1iA ... j&index=22
Crafting an ooa wand that has good stat is a pain, so what I did is use ooa on swap, cast until mana is empty, go back to my normal set up until mana's back and repeat. But it can be done without the swap too (I'm just addict to adding more buttons). As you said it's a really nice spice, doing it like this is far from amazingly good of course, but I had lots of fun playing it, which is what matters.
Also, because I played like that, if you wanna use ooa as your main attack I can't give much advice, I did not attempt to gather enough mana and regen to make it work, but it should end up nicely.
I was hesitant to talk about oskills in general in a separate section but I ended up only mentionning them (it's only ooa and singularity anyway) in rifts/dungeon they're useful in.. Presentation in a way everyone get the info is hard.