The diesel-powered GTI will be called GTD. The Mk4 Golf didn't have that version, but all the rest did. It's a tradition, similar to GTi. The new GTD will have a 2-liter TDI with 170HP and the torque of a Cummins.
I've also heard of many problems on VW's built in Germany (or the rest of Europe), so the Mexicans are not to blame. The recent years have taken a lot of VW's audience in Europe. people see them as no better than French cars, so they buy the same shitty French cars for less money and with far more appealing designs and with more practicality. The French have been building very original and practical people movers for a decade, the Germans have only started in the recent years and still seem to be a bit comfused.
Regards,
Martin