Is your Daemon Prince really better than a Bloodthirster? He is just 10 point shy of being as good as a D Weapon carrying Bloodthirster that eats Imperial Knights for breakfast? I'm not convinced.
Plasma on the
CSMs is wasted as it denies you charging. So you've payed for over costed Khorne Marines, further upgraded them with
CCWs and bolters and then bought them special weapons they can't fire and assault with. Drop to melta. Icon is only worth it in my opinion if you're taking an axe of Khorne for S5 Ap2 at initiative. I would drop that too. Swap bolters for
CCWs, get extra
CCWs on the 2 special weapon guys who carry melta (helping with the massive
AT issue the book has) give the leader a power lance (he has to challenge) a pistol and a combi melta and if you're taking a weapon on the Rhino make it a combi weapon too. That makes the squads just 246 points (saving you 78 points) and now they tote 4 melta shots each and retain the same attacks on the charge. Marines are overcosted don't compound that with unnecessary upgrades, only ever take what you HAVE to, to get the job done.
Possessed need a Rhino to add anything to the list or you are effectively playing 150 points down. Giving them a Rhino also adds to the metal box saturation.
I would ALWAYS take the Insensate Rage thirster if taking one in the list. Daemonkin suffer with poor
AT and little ability to deal with Knights. Insensate Thirsters plug both gaps. The changes above will leave you with enough points for this and the Possessed's Rhino.
That Termmie unit is Expensive! Terminators are not good against Hordes no matter the build so I would leave the
HF at home. I would consider dropping the unit down to 4 and adding a Chaos lord here (instead of the
DP). A nice trick can be give Kor'lath the axe of ruin to your Lord. Then as soon as you get to 7 bloodtithe sacrifice the lord to become that
DP. Since the lord dies in the process you also get a free Bloodthirster. Yet the Prince gets to keep the axe so wjen he dies you get yet another free Bloodthirster

.
Hope this helps.