Continuing the approach used with the SD70's and ES44's on any Legacy diesel offerings, i.e. scale wheel options, DCC compatibility and Kadee mounting pads. The flexibility of those 2 models was fantastic.
Doing the same with Flyer Chief locos relative to scale wheel options and Kadee mounting pads
Rolling stock - More realistic sizes trucks akin to SHS, AM or SSA with scale or hi-rail wheel options; and Kadee mounting pads