Two things: GM can't even keep a supplier solvent ( see other thread) and the very questionable reliability of the 1st Gen Diesel is surely going to kill sales of the Gen 2 whisper diesel.
The only reliability issues I've heard of on the Cruze Diesel's has been emissions related items mostly sensors and such... Whereas with VW, they sold 450,000+ of the Common Rail TDIs over the past 7 years with the cheater software and VERY Questionable reliability. Just look up HPFP failure, it's some fun reading. Oh and when a TDI HPFP (CP4 in the VW, the Chevy uses the more robust CP1 variant) fails it takes out the entire fuel system resulting in a bill of around $5-8,000 to repair/replace. Even once these issues became widely known sales were still strong.
So if GM markets the 2nd Gen Cruze Diesel well they should have no problems selling them. Afterall there are something like 390,000 VW TDI owners minimum that the agreement will require VW to Buyback or repain, and there is still not an approved repair and the Euro repair is said to make emissions AND performance worse so the vast majority of VW TDI owners will likely eventually turn in their cars for a buyback. GM just needs to market directly to them and give them a good car and reason to buy it.
Personally I think they should sell the 2nd Gen Cruze Diesel with the 1.6L as a Jetta/Golf TDI replacement in both sedan and hatchback. Then additionally sell the new Malibu with a revised version of the 2.0L Diesel engine the 1st Gen Cruze used as a Passat TDI replacement.