I'm curious. Why are people so against changing a Nintendo Red Tent?
For the same reason people don't want to change any classic arcade machine....Keep the machine original.
At least as much as logically possible.
For me, I think the most important items to keep original are the ones your interface with. ie: control panel, buttons, joysticks, monitors. Basically anything the player directly interacts with. The monitor is the probably the best example of this, so it a big part of the "original" look and feel of the machine.
Now if you want to switch out a sketchy power supply for a switching power supply? Go nuts. But an original monitor is worth making a good solid effort to keep.