It seems like the counter is real time so the message feels scrambled and could be different at any time. for example, some people are getting S (or 5), E, 3 while I got 3, S (or 5), E. You would have to watch it a few times to see where the loop begins and where it ends. My bet is it will be a special edition of 4 revealed at E3, but you know Kojima...
Maybe Kojima has had MGS5 planned for awhile (doubt it though). If they do that I hope it would be around the period where Raiden rescues Sunny and gets captured by the Patriots. I don't really like Raiden but it seems like the only way you could do another Metal Gear without screwing up the plot, and the whole lightning thing people keep bringing up.