The 3 kingdoms version:
Why: I think if there's more distance between clans they'd be more likely to fight each other. When clans are too close to each other, wars between them won't last long so they don't want to fight each other, leading to more alliances than conflicts.
On the NA side we had a good Green vs. Red war for a moment. Splitting the NA zone into 3 areas would give both former Red and Green clans places for their home bases with a little safe distance between each other. The third area would be a good place for neutral clans, new clans or anyone not involved in that conflict...yet.
With the current setup of one large NA zone, allies tend to choose territory next to each other anyway so splitting the NA zone would just make who's on what side a lot clearer. It would also give certain areas of the map more strategic significance for both NA and EU.
Addition benefits: There would be more trade and interaction between NA/EU clans since they'd have to cross each other's territory, possibly leading to less of the NA vs EU mentality that strat v.3 descended into toward the end. This map would also spread out the EU zone as well giving them the same benefits of having more distance between adversaries.