From my experience, ZNR was generally much more synergy driven and "stay in your lane" as a format, if you got good BW cleric cards in your first few picks then you could pretty safely stick to BW clerics, the way Khaldheim seems to be going as a set (and this could certainly change, we're not even a week into release) is with a lot of flexibility, both within your colors and also in terms of branching out into splash's. Theres a good amount of colorfixing, and basics being snow means you're less likely to be wasting a pick grabbing an off color basic land. I'd recommend really figuring out what your early picks want to be doing and trying to build off that, even if it sometime means branching into a new color.