My 1955 Raleigh Lenton "Reg Harris" has a cottered crank, steel rims, and 531 tubing.
But the cottered crank is a track crank with a removable chain ring, the steel wheels are the factory 26 inch Dunlop EA1 (stainless) and are some of the smoothest running wheels I have ever run.
It is also a fixed gear (stock) and I have laid down some pretty spectacular times with it.
On the stand I can spin the crank and wheels and they also seem to go forever such is the quality and smoothness of the bikes (oiled) bearings.
Basically...cottered cranks and steel wheels aren't always a bad thing.