Sorry to be late in the discussion. I too seem to have gotten caught up in reading all the PI material.
It seems that the RoPs are getting good relative numbers in the polls. However, I plan to vote Abstain. China and Russia can both engage Babylon without setting foot in Fanatika, and as Cyc mentioned, an RoP w/France would not sit to well with the Iroquois.
However, my vote to limit RoP's now is actually part of a bigger picture. I think that starting now and continuing into Term 6, we need to formulate a perimeter defense that will allow us to confidently say to any approaching civ, "Leave our territory or declare war!"
Have we said that to anyone the entire game? Just think..... England traipses all the way across our strategic routes to engage Japan, only to find out that the war is over. So back they go, once again becoming obstacles in the process. When India struck the North Province, there stood Babylonian troops near Strider's Haven impeding the relief efforts of our Taliesin knights. And speaking of the Indians.....well, we all know how that turned out.
As our FA Leader, please tell me the possible repercussions from enacting a closed-door policy upon other civs. I am aware that this could greatly affect our alliance options, but maybe the time can come where a nation on the other side of the world doesn't need to join the fight. Of course, we should not adopt this policy until our borders were well fortified, but it's a goal we should strive for early this term.
As far as an explorer wall......the mightiest nation in the world would resort to a game of Red Rover to fool the computer?

Well, I would rather fortify with riflemen in mountains and a few more units of cavalry at the ready in Padmativa and Leningrado. Let's do it the more realistic way and keep our self-respect.