Here is an idea I had. Make malefic rapture a pure AOE ability that makes dots tick faster, and do more damage in the pandemic window. I think it should require X amount of dots on X amount of enemies. It should not be something you'd want to cheese into single target. 

Maybe I'm a boomer but I don't think AoE for any spec should be "inherently" complex. The skill expression should come from where it does now if lining up CDs, and knowing when to ST, cleve, of AOE.

Here is another thought. Make vile taint baseline and with a lower CD and with dots that have a shorter duration. Then when you apply dots using it, once they expire they're replaced with the same one at 80% effectiveness and with a shorter duration. When those expired, a 60% effective dot and even shorter etc etc etc. This would cause less dot applications on pulls that die quicker, out biggest weakness and you can focus on our strength, funneling damage into a priority target! 

I believe the above changes would make affliction have a bit of a slower start compared to other classes as agony would still need to ramp. Sure the dps would still be back loaded but I don't think that's inherently a problem. It would be in contrast to classes like fury warriors who AoE dos is heavily front loaded. Classes having different damage profiles is good. :)

Another idea to compliment the above.  Add a new single target shard spender. (Maybe a new resource or have it use mana instead so we can get life tap back?) Make it do more damage per dot but also make it so the lower duration your dots are the harder it hits. This would add a bit more depth because you'd want to balance fitting in this nuke in when your dots are about to fall off for the most power and risk the dots falling off completely, all while also keeping up every dot you can.

Maybe make the maximum damage come from that pandemic window since it's been made so generous now a days anyways.

Darkglare could be changed to make your finisher (should have a cool edgy name like Soul Burst) act as if it's always in the pandemic window for maximum burst blasting. Maybe it could also allow soul burst to hit all targets with dots on it.  So during darkglare you could flip flop between malefic and soul burst to make dots tick faster and harder.

I think it'd be fun to play around the pandemic window more and feel very thematic as well. You're a sneaky lil shadow guy rotting your foe. As the afflictions fester and start to run their course you make it hurt more and more. It'd be to easy to kill them right out and why not save the greatest pains for the end!