The reason the accession of the Central/Eastern European countries was done so hurriedly (fredouil mantions Turkey being large, poor, extremely nationalistic and not prone to compromise - which unfortunately describes Poland) is partly to do with trying to prevent disillusion with democracy to set in in these countries if they had been told they had to sit out in limbo for another 10 years. Turkey is not a new country or even a new regime: it's been around in essentially the same form for 80 years.

The idea that accession would help bring these countries more in line with EU standards has been proven false, though. Accession candidates have every incentive to do what the EU tells them to satisfy accession criteria, but once they're in they get the carrot and the EU loses the stick (or they get a stick, too), so accelerated accession was probably a mistake on that account, too.

But, like I say in another comment, Turkey won't join the EU for another 15 years at least, so I don't see any rush.

Those whom the Gods wish to destroy They first make mad. -- Euripides