-It's not really part of Europe
It is very hard to define Europe - do we base it solely on geographic proximity? If so then Morocco is more European than many of the member states of the EU.
-Human rights record in Kurdistan
-Censorship and civil liberties. They just recentely arrested a journalist for writing about the Armenian genocide
-Northern Cyprus
They are required to reform on human rights and civil liberties in order to meet the requirements of accession - having potential EU membership is a better way to get Turkey to reform than to totally close the door - ultimately I think it should if it meets the requirements for accession.