Below I've done a very rough map of what the split proposed by Locke would look like, for those who are wondering. Based on the culture, history and geography of the regions, I think this seems pretty sensible. Obviously there are a couple of anomalies but none that are too problematic, as we've noted there is no reason that seats must exactly reflect history and politics.
Auditorii makes a good point about the activity of the "Third World", it fluctuates considerably over time. At present we have about ten countries that are formally "controlled" and only about seven or eight controllers (Wu Han and I control four countries between us). On a related note, a couple of these countries are controlled by players who already effectively control a Security Council member (Kubrick in Vanuku, Auditorii in Ostland), although it's obviously not the case that they will continue to do so.
With all of that said, the current Security Council does have reasonably robust procedures for ensuring activity. In this term we've already managed to have all eight countries vote on two separate resolutions. Applying a modified form of these to the "Third World" seat would hopefully ensure activity from these members too. Personally I'm optimistic that between us we can ensure that activity can be preserved so at the moment, I am in favour of Locke's proposal of a northern and southern Third World seat.
Whatever we eventually decide, I think the consensus is clearly in favour of some form of representation for the so-called "Third World" countries on the Security Council. For that reason, I'd like to have a proposal agreed by the beginning of the next term (1st June) so that we can implement it then. If we are going to vote, we'll need about a week beforehand to do so. This leaves us a good couple of weeks to work through the details.
I have attached a poll to the original post in this thread to see if there is any clear consensus either way. Voting for the "two seats" option does not necessarily mean an endorsement of Locke's division so feel free to share if you have an alternative proposal. Note that the result should not be considered binding in any way, it's just a tool to help to gain a broader picture of player opinion.