As with GF the first step is to understand how the List works.
Unfortunatelly for us, Dark Host is quite a versatile list compared to GF.
Assuming a Denny1 GF pairing we know we wont see her, but after that there are a lot of casters floating around.
The build itself will also be more different from player to player. The reason for this is the existing love for Banes in Cryx and the simple fact that more people already own bane models.
First we have to think what they will probably cover with their Dark Host lists. Immediately comes Circle to mind and probably Ret, together with Gunlines that can handle the pirates, thus shooting might not be the best idea
That said, lets get into what we know:
Bane Knights are probably the least taken variant of the Banes, and also the least good. They may have a lot of armor, but Cryx players don't think they hit hard enough
Bane Warriors will be in every list to a certain degree, just because of dark shroud. They hit hard but are fairly slow. They don't have the best defensive stats but bring tough and a bit of recursion.
Bane Riders are a current favourite of many cryx players as they are really good with the Wraith Engine against shooting (or arm buffs in general). Expect to face those guys.
Wraith Engine will be seen in many lists, as its one of their best techs against shooting and its just a good piece in general
Tartarus is the "standart" free solo and I don't think we will see a list without him. He buffs the mat to Mat7 (8 on the Riders) and hits quite hard
Daragh Wrath will be seen in some lists as he increases the tankyness of the list or speeds them up which are both really good effects for the list.
Jacks we be most likely ArcNodes, Stalkers and eventually Descecrators. For those of you who don't know what the Cescecrators does, he is basically a Destroyer that leaves a 4" Corrosion-Stlye template.
Casters will be all over the place as mentioned before.
L&L was won by a PSkarre list, which fixes the hit issue while also bringing even more hitting power
Goreshade3 is also a very popular list with the Bane Riders build (2 Bane rider+WE+min Warriors). This list is particularly effective against shooting and brings recursion. Should not be a problem for our Butcher3 anti-GF builds.
Gaspy2 brings a cloudwall which, together with prowl, protects the banes quite succesful against shooting
Scavarous brings controll, thread extension and armor
And so on...
so what to do? Killing single wound infantry with high armor is all fine and well but in many cases its the wrong way to plan.
As I mentioned Bane Knights are going to be far and few in between, so if you encounter high armor, its most likely going to be on 5 hp riders.
Jacks are going to be problematic since Bane Warriors just kill them very easily (pow13 WM).
I think our best bet is either going to be a mixed arms Butcher3 build like we already use against GF, or LoS.
In LoS we outthread almost all banes and have no problem killing them. Arm from Strakov2 will not help a lot but Tough might and just the fact that we have more modells than he has.
LoS is tricky against GF, maybe
drnorbert has the right way in just clocking the GF opponent, but thats no easy thing to do.
The problem for Los would be desecrators, since Corrosion templates are really not nice.
Btw another thing to watch out for is that banes collectively ignore terrain and freestrikes with ghostly