Karl, almost all the suggestions in your 5th paragraph already exist. Every S gauge engine Lionel has made since 2014 will run with either DC track power or AC track power. All Legacy engines since 2014 will also run with DCC. The entry end command control system is FlyerChief, I do not think those are very expensive. There are in fact many of us S gaugers who do want highly detailed Legacy engines. A challenge for us and for Lionel in S is, unlike in O gauge, the number of purchasers drops dramatically for engines with a street price above $1,000. Lionel does not include pre-wiring for a DCC decoder in their conventional engines, but neither does American Models.
It is very unfortunate the club's Polar Express Berk encountered all those problems. My experience with a fleet of 46 Lionel command control and AM engines retrofitted with Lionel TMCC has been very few failures outside of smoke units. In club and public display layouts the smoke units are usually switched off so a bad smoke fan would usually be unimportant.
All the old Gilbert engines can run on DC track power. Many operators have retrofitted DCC into Gilbert engines but that usually requires a can motor. Drop in can motor conversion assemblies are sold by several vendors and are not expensive.
I like the sounds of what you would like to be able to buy, the challenge is probably that the S gauge sales volume is too low to support several different engines at that price point.
I do not see Lionel dropping the American Flyer line, at this point they are the largest supplier. My concern is about the mix and frequency of new products.
