Speaking as a PAOK fan, the only truly young prospects I see playing for my team these days are Konstantinidis and Koulouris. Maybe Pozoglou, although after a good start with the senior team, he's gotten absolutely no time yet (probably a sign of him not being as good as I like). I believe one of Koulouris and Pozoglou are banned as well, anyway.
So that leaves Konstantinidis. Tzandaris had the benefit of lots of playing time with very low expectations, combined with an offense that was scoring for fun. I don't dislike him (he reminds me of a less aggressive Kace), but I think his mediocrity was covered up by those other points. He will end up in a midtable team, as Blackhawk used to say.