There actually are some good things to the 'outdated' electrical design. The circuits are on conventional PC boards with 'standard' DIP integrated circuits. Just about any contemporary electronic device today has a circuit board made with SMD components and these are nearly impossible to repair or modify. Also, the D5500s primitive origin means its circuit is less complex and easier to understand and troubleshoot.
If I were to use an automobile analogy, though, I would have compared the D5500 to something like the Bricklin or the DeLorean. I think you will agree that the D5500 was a pretty modern design for 1982.