Mandrakes are really bad ... Reavers are meh, too.
Double your Incubi. 5 won't pack enough wallop or endurance.
Consider adding Yvrainne and exploiting Soul Burst while it exists before the next
FAQ nerf.
DE right now don't have the tools to handle the 8e meta. The Turn 1 Deep Strikes are going to punch in your vehicles and there goes the show.
I am doing poorly with Chaos Daemons and
CSM, but it was no problem to demolish a Drunkari army in a tourney last week. He was a better payer than me, but couldn't handle a Turn 1 Blood letter bomb.
DE need the screens scouts, nurglings, rangers, or cultist/conscript speed bumps provide. So, maybe Yvraine and some rangers?
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Or, can all of my advice and wait for the Codex to drop.