There are some points, I would change:
Get lost of the agonizers and the demi glaive. Get 2 wyches more, to make it 10 per raider.
Give your klaivex onslaught and the reavers caltrops. If you got some points to spare,
include a haemi. And maybe get a tenth cabalite warrior with a splintercannon.
Hm, regarding the duke:
I thought of something. How about a pack of splinterborns. Say four. 2 with splintercannons, 2 with carbines.
Stick them together with the duke in a venom, et voila.
Hm, is a dedicated transport part of the unit? In game terms? Because if it is, it would be perfect for the duke.
When I'm good, I'm very, very good. But when I'm bad I'm better.