I'm a fan of the stationsounds cars, I miss it when one isn't offered.
I may be more hesitant to order any high end sets in the immediate future due to other reasons relating to quality control, but for any set I do decide I want to purchase, I really would like a sound car to go with it.
Also (my opinion only, I'm sure other people more concerned with prototypical accuracy would disagree), I would be OK with having sounds in either an additional diner (or even an additional baggage car). As far as my tastes and constraints on how "real" I need my train to be, the only car that I would never double up on is the observation car, which obviously would not look good, IMO.
(recognizing there may be an odd case here or there - I have in my mind seeming to remember reading somewhere about an observation car that might have been placed at either end of the train, so the train could be pulled in either direction and always have an observation car on the tail end without turning the train around. I don't recall if that was totally fictional or an accounting of an actual train that existed in real life)
I bring this last point up because it was pointed out to me in another thread where we were discussing SP passenger sets that a 6 car set (the one marketed as the Shasta set to go with the PA-1s - 4 pack plus 2 car add on from around 2010) actually already had a dining car included within those 6 cars, so maybe that's why Lionel never did a stationsounds diner. I would have still purchased a sound car even if it did mean having 2 diners in the train.
-Dave