Microsoft’s Joseph Staten said that limiting Wrecking Zone to 5v5 in Crackdown 3 was a design decision, not a technical constraint.
However, that’s exactly the opposite of what a colleague of his, Jorg Neumann, said a couple of months ago.
Source: N4G PC Crackdown 3's 5v5 Wrecking Zone Multiplayer Was a Design Decision, Not a Technical Constraint