We drove down this road today in our hired Corsa and it was absolutely fine, in fact one of the better Greek dirt roads we've driven on. A smooth, compacted dirt surface with a few small loose pebbles but no large stones and no pot holes. Lovely views and it took than half the time of our ascent via the paved route. I have seen dire warnings about the state of this road but I think these were from people who drove it in the spring, after the winter weather had messed it up and before the annual (I assume) scraping and levelling.
Of course if your insurance does not cover you for driving on unsurfaced roads you are taking a calculated risk but the condition of the road at the moment should not worry anyone.
I will post a full trip report in due course!