It certainly looks like a nice frame.

AFAIK, the paint is there to keep the metal from rusting and aesthetics. The paint appears to be in decent enough shape to protect the frame, so it comes down to appearance. I'd probably just leave it as it is with a good cleaning and maybe some wax.

That's a broken cable guide on the top tube, not a ferrule. That must have happened because of handling because they are not under stress. If you decide to have the frame painted, you could get someone replace that for you. I believe they would file off the guide and braze another to the frame, but the might heat it up to remove it. The heat would, of course damage the existing paint.

You might be able to file the cable guide down yourself. Just be sure that you don't cut into the material of the tube. Then you could glue another guide at that location and paint it. Nova Cycles sells frame parts. Or just buy a bolt on guide or use a zip tie.