I think the "simplified dining service" has evolved into something much more similar to the "standard" amtrak dining cars. When I think of SDS I think of the Bob Evans Breakfast Scramble, not the made to order scrambled eggs that are now available on the menus. What remains of SDS is reduced staffing, plastic plates, paper tablecloths, and possibly a couple more pre-made entree's than in some prior Amtrak years, but nothing that noticeably different in my opinion.
As for the City of New Orleans, the CCC car when I rode last summer was being used basically as a standard diner, and served one of the best meals I've had in the past few years anywhere, no just on trains.