The stuff you're proposing I could probably do myself.
What I really want is a lower gear ratio, and maybe a 5-pole armature. Basically enough speed control that you could turn the loco on and let it run without fear of it leaving the table. Diesels run ok, but most postwar steam locos have very poor speed control. A look at the number of broken marker lights, bent cowcatcher steps and cab roofs seen at train shows bears me out.
This kind of upgrade would take some original engineering, probably a whole new chassis (or at least re-drilled side plates with added gears and gear studs, etc.)
I keep waiting for Neil Young to influence Lionel to produce a 2018 replica with Legacy. We can hope! -Ted