I see your point Alan, I personally think that the service times are more the lack of motivation/cooperation of some crew rather than SDS. When I rode the Capitol this summer there was one LSA, one server and one (assuming) chef. The whole diner was full for lunch and service was very quick. To me, this was proof that it could be done it just usually is not (the day before, a half full diner on the crescent took twice as long to serve breakfast with the same # of crew).
I'm at a loss to figure out how they could pull that one off. I surely wouldn't want to run a resturant with 20 tables and only one waiter. The general rule is one waiter for 5 to 6 tables, if you want to provide good service. And that's before adding the complexities of working in a moving resturant.
Question, did they only do one seating? They used to be able to do three pre-SDS. And did they seat en-mass? Or was it still staggard a bit.
I also have not seen the new SDS seating times in practice, the LSA's are always seating people just like always telling people to come x time or x time, not two tables at 5:15, two tables at 5:30 or however that plan goes. So I see very little problems with the current dining car. Perhaps its worse on other trains though. If I had seen what you have seen, I would probably agree with you.
I've noted many crews that seem to have made up their own rules regarding the seating plan. A few that were better, meaning that they actually seated more people than the plans call for, some that at least got the same amount of people through the diner (even though service suffered a bit), and a few that got less through the dining car than called for. The later of course resulting in less revenue for Amtrak, and in one case several upset sleeping car passengers who didn't want dinner starting at 10:00 PM.