The EU shouldn't be there to solve Turkey's problems. It may have been the case in the past with Spain, Greece and Portugal admitted for political reasons but the EU is a different entity now. If Turkey is to join it really needs to have all these problems sorted out already.
You probably shouldn't read too much into one murder but there does seem to have been a rise in Turkish nationalism in the past decade. Theres a growing anti-Europe feeling and I really can't see them joining, even if the Cyprus problem is sorted out.