My wife has a Cruze Diesel that I will be deleting next weekend
A trusted online source who has 14 Cruze really liked the few days he spent with the new one. He felt the lack lack of power was more than made up for by the lighter weight. Some of the Cruze folks like the new car better and some don't, my guess is the diesel will be fine for those who like the new car.
Now the problems with the old car are completely emissions related, I've yet to see one issue that was not related to a sensor in the exhaust pipe. My car is a joy to drive and was flawless for 45000 miles. My wife hit a deer and had the hood, grill and all the cooling apparatus replaced and it has needed to visit the dealer every couple of months for the last year and a half. I blame it all on an O2 sensor that got bent in the accident and was replaced. Every sensor downstream has now acted up and been replaced at least once all on GM's dime. A couple of weeks ago she took it in the have the O2 sensor replaced for the 3rd time and they found a NOX sensor which I didn't find when I scanned it and they wanted $900 because they won't do anymore warranty work on it. She laughed at them and told them she would just delete it all. They gave some big speech about it being illegal and fines and EPA so she said she will never buy another Chevy as she drove off.
I like it, it's fun to drive and gets good mileage if you don't go 85 on long trips like we do. Even at those speeds we get mid 40's, it's been to Vegas and Phoenix and next month were expecting to see better mileage when we go to see the Mouse in Florida with the new light weight exhaust. What I wish it had was a community like this to figure things out when the mechanical stuff starts to wear out.
If I had to make a guess, I would say the 2018 Cruze Diesel should be good, let them work through the bugs first. The diesel trucks had issues at first, but they are few and far between now, I think the cars and smaller diesel trucks are getting there as well.