Well the Norton Featherbed frame has always had the reputation of being the best handling of the multis from the UK, while AJS and Matchless had the same reputation for singles. Riders 'of a certain age' will fondly recall the Tritons which placed a Triumph twin into a Norton frame, in-search of that elusive 'handling' quality that Norton had, but Triumph didn't, in comparison.
I am in agreement that the bike should be finished. It's such an oddball, you won't see another. Someone wanted to use the best-handling period frame, and another era's most-powerful engine, to create an era-jumping, 'what-if' moto-jumble of parts to make something truly unique. I think to be safe, I would want wider wheels and radial tires ('tyres') but I suppose just finishing it as-is would be an exciting ride.
Note to max midnight: one died in a motorcycle accident, the person who bought it from the estate did nothing w/it for decades, then he died, and a relative got a bunch of cars and bikes. He liquidated most of the rolling stock but kept this. I hope he finishes it, I would like to see it run, and to hear a ride report, or how it compares to say, a stock Mach IV on a road course. Now, that would be an interesting experience.