Our top 3 units under the Ynnari banner from best to worst are:
1. Reaver Jetbikes
2. Scourges
3. Medusae
So i'd spam the living crap out of them, specially the first two.
Looking at the troops slot, wyches actually got kind of a boost, as you are now able to use them as tarpit units as they gain stubborn. I wouldnt recommend spamming them but if you're gonna go pure Dark Eldar you might as well want to consider them over warriors to cover your mandatory troop choices for +10p/unit, as the latter dont benefit from being Ynnari whatsoever.
Scourges work better with 2 or more units, as you almost guarantee blowing up your target to secure soulbursts to either repostion out of harms way or blow up another target. I would recommend heat lances by DS.
You probably have noticed that our best Ynnari troops all compete for the FA slot. I am having sucess with multiple Reborn Warhosts, as you get the added value of multiple soulbursts derived from the Host of Ynnead rule with smart positioning. Just make sure each has 7+ units in them.
I'd undoubtedly take an MSU approach to it.