I don't see why Greece doesn't play 3 at the back like Italy. It has worked so well for the Italians and both teams currently seem to have a similar makeup where their strength lies at the back. Greece's potential backline of Papadopoulos-Manolas-Sokratis would certainly be one of the most feared in Europe. Further, we have very offensive-minded fullbacks with midfield experience in Holebas and Torosidis, solid holding midfield centered around Samaris, and some capable offensive weapons in Fortounis and Mitroglou.
I'd love to see this tried out before the WC campaign.