That's a more general deckbuildimg concern; just make sure that at least one side can cycle cards well. Again tho, this is going to vary deck to deck, not culture to culture. You can make uruk decks that cycle well (using
Abandoning Reason For Madness, etc), and you can make uruk decks that clog like mad (if for instance you relied too much on swords and events, which are dead in your hand if you draw no uruks). The only time this isn't true is when a culture only lends itself to ~1 strategy, such as Moria frequently going for hand extension.
The question you need to ask is what *strategies* pair well together. Making a shadow bomb of any cultural flavor requires a freeps side that can easily cycle and stand on its own with just what's on the table--a pipeweed deck, perhaps. A lot of freeps-focused decks will require the opposite, that shadow be able to set up and stop your opponent without a lot of specific cards in hand--card slots you'd rather be filled with freeps cards.
No offense, but if you're asking these questions I'd think you have a 50/50 chance of building decks that end up hard to teach with. If the starter decks don't appeal to you, maybe search this subforum for pre-built decks you'd like to use instead.