Since Lionel is finally releasing their new Base-3/Cab-3 System sometime next year, I think that an upgrade to their LCS system would be a good idea. Let me know if you agree with me. I also have a few other suggestions for features and products.
-The LCS App could be given some major updates for control over the trains and a much better selection of track pieces, including more curves, smaller straights, operating tracks, and crossovers. Tubular track sections and American Flyer track could also be included as well.
-A new Accessory Voltage Controller would be a good addition to the LCS system. The new AVC could have direct connection of a 135W or 180W Brick and a PDI connection to the Base-3 (PDI Cable sold separately, of course).
-I'd also like to have a dedicated Operating Track Controller (OTC) to control operating and uncoupling tracks (especially Fastrack ones). Using FT Operating Tracks with an ASC2 requires modifications to the wiring (Sean of Sean's Train Depot on Youtube did a video a few years back that illustrates the necessary modifications, and they are pretty simple to do).
-Lionel should remake all their old operating accessories. Maybe they could add command-control to some of them, especially the bascule bridge and intermodal crane.
-Lionel should make larger O84 and O96 Remote/Command Switches. Atlas, Gargraves, Ross, and MTH (Scaletrax) all have larger switches for crossovers and yards.
-Wi-Fi Cameras in locomotive cabs (like the cabooses and vista dome passenger cars) would be awesome.
-Modern diesel locomotives need rotating bearing caps.
-Lionel should bring back road name/road number specific dialogue for all engines.
-I'm still hoping for a Fastrack Turntable (similar to the Atlas O one). The turntable could be sold as a manual version, a motorized version, or a TMCC-controlled version. If Lionel opts not to include a TMCC board with a FT Turntable, an AMC2 would work for command control.