Changes to Keywords and List Building
The biggest change to list building are selectable sub-faction keywords such as <Chapter>. Originally these were picked on a unit-by-unit basis, so squads and Detachments could come from different subfactions. This selection is now made when you start to build your list, and the sub-faction you choose now replaces every example of that keyword – meaning your whole army now has to come from the same grouping.
This keeps your armies – and your opponents’ – from becoming overly complex, ensuring that the unit compositions and synergies you build in your lists can provide an interesting, evolving challenge.
There are a handful of exemptions, as you’d expect – named characters have a pre-selected keyword, but are exempt from the restriction, while <Mark of Chaos> and <Allegiance> keywords can also be different – so Bel’akor’s unaligned daemon armies are still viable.
Super-heavy Auxiliary Detachments also encourage a unified army, as they can offer a Command Benefit of +2 Command Points if the Lord of War choice shares a faction with your Warlord (other than Chaos, Imperium, Aeldari, Ynnari, or Tyranids). Combine that with an upcoming points drop, and it looks like Monoliths are back on the menu.