Making up with Serbia doesn't seem a likely immediate solution either, at least until the Kosovo and Montenengro situations are stabilised. But it really is in Serbia's interest to make up with the EU ASAP. Otherwise it will be bypassed by history as well as by the EU transportation network. notes from no w here
And really, when it comes to land, I don't think that even joining the EU will mean more to people.
But from the point of view of Greece I think they would have preferred that the EU had made a special concession much earlier to build a road through them once it was realised that Serbian isolationism effectively crippled Greece's ability to trade with the rest of the EU.
I wonder if Greece's turnaround on Turkey is to put pressure on the eU to get the eastern europe routes through R & B sorted out quickly. keep to the Fen Causeway