Ignoring the upcoming codex changes- you don't need to ever add an auxiliary detachment like that. You lose all obsessions in an auxiliary detachment, so wouldn't be able to give those Talos a 4++ or Dark Technomancers. Rather, try to take advantage of the Raiding Force rules that allow you to take three Patrol detachments without having to spend command points. Drazhar is a free-flowing HQ choice (as are the Ynnari characters), so if you add 5 Wracks then you have a Patrol detachment of Drazhar, Wracks, Talos that can pick any of the Coven obsessions. If you aren't looking at three Patrol detachments just yet, it's better to stick to only Kabal units for your single detachment.
Taking the upcoming codex changes into consideration- it is likely that the rules will be very different and affect army composition. GW mentioned you will be able to mix Kabal, Coven, and Wych Cult in the same detachment without losing all the bonuses. I would expect Talos to come down a little bit in power, while weapon profiles for the Ravager should change to be more effective. Comparing the two units will come down to efficiency for their new points costs as well as how the obsessions/stratagems will change.
If you're looking for something to build/paint/use for the next couple months, I would suggest the Ravagers to boost your current list.