a lot of folks have posted remarks on its high power level. How will this affect the Witch Hunter codex, when using allies from the Imperial Guard?
To include any of the juicier stuff, like Leman Russes and Sentinels, the Witch Hunters must include two Troops choices, either Imperial Guard platoons or Armored Fist squad. Seeing as the Armored Fist no longer exists, RAW (interpreting the Rule As Written) indicates that two platoons is the only way to go.
Fortunately, this can be both cheap in points and bolster your numbers quite nicely. Equip them with Autocannnons or Lascannons and place them out of harms way. The Battle Sisters should have Melta duty in Witch Hunter armies, the Guard should provide long range support.
Even though the Platoons somewhat mitigate the Witch Hunters' weaknesses, the other choices can do this even better. Sentinels, with their outflanking abilities, can give some much needed special movement options.
It is still unclear if the Witch Hunters can take the Sentinels, as their title in the codex have changed from "Sentinel Squadron" to "Recon Sentinel Squadron" and "Spearhead Sentinel Squadron".
Even more important is if the Inquisition can take the Leman Russ squadron, or only a single Russ, or whether they can take them at all. By RAW they probably can't but with some FAQ goodness, hopefully this will enable the Inquisitor to order three mighty battle tanks to fight against the witches, daemons and aliens out there.