Firstly I am all about the Succubus with Agoniser. Not quite the tempest of death she once was in 5th ed, but still awesome at putting the hurt on when it counts - unless she gets challenged by a multi-wound character in Termie armour with a hammer/chainfist, but enough of that.
Seen a lot of DE attaching Farseers to their force but with you here i'm not sure its adding much. Yeah you may shut down some psykers, which is good against the ultimate DE uber-smashing nemesis of Grey Knights, but I would squeeze in another venom for that cost.
i would be inclined to swap your Heavy Support around and take 2 Razorwings or a Razor and a Bomber for some skyfire goodness, and also since they are hard to hit and can really put the hurt on Infantry.
Not totally conivnced about PGL's on wyches. I suppose their worth it when you get charged by standard marines, but against Death Co, Orks, CSM or SW its not making a huge difference. I would put in an 8th wych, or hydras or shardnets for the pts your spending
I really like Incubi as you can probably tell by my avatar, but I would put them in a raider and take at least 6-7. They are not that great these days, but they have a fearsome rep and will provide a good distraction for your opponents shooting. And if they survive, get them into those squishy Long Fangs, Devs etc
Good Luck!