I'd think a well-seasoned Koetsu Roswood would be well worth rebuilding.
However there are some caveats. If the last re-tipping you did was not by Koetsu, they may not accept the cartridge for rebuild. The only place that rebuilds Koetsu to sound like a Koetsu is Koetsu. If it was done somewhere else, you have some kind of hybrid, that is not really a true Koetsu any longer.
If this is the case, I would recommend getting a different cartridge like the Shelter. The arm/cart matchup will be almost exactly what it was with the Koetsu. The Shelter cartridges have a compliance rating of 9cu, and so does the Koetsu. Weight is also similar.
The Shelter 501 or 901 are awesome cartridges, and would not disappoint you. They are made by some of the old guys that used to build the Fidelity Research cartridges in the old days, that were considered to be competition for the older Koetsu. The Shelters have the classic Japanese MC cartridge sound and are continuing that tradition. There are not many others who are. Also, the Shelter cartridges are very affordable compared to the others, and the sound is competitive with the best.
However there are some caveats. If the last re-tipping you did was not by Koetsu, they may not accept the cartridge for rebuild. The only place that rebuilds Koetsu to sound like a Koetsu is Koetsu. If it was done somewhere else, you have some kind of hybrid, that is not really a true Koetsu any longer.
If this is the case, I would recommend getting a different cartridge like the Shelter. The arm/cart matchup will be almost exactly what it was with the Koetsu. The Shelter cartridges have a compliance rating of 9cu, and so does the Koetsu. Weight is also similar.
The Shelter 501 or 901 are awesome cartridges, and would not disappoint you. They are made by some of the old guys that used to build the Fidelity Research cartridges in the old days, that were considered to be competition for the older Koetsu. The Shelters have the classic Japanese MC cartridge sound and are continuing that tradition. There are not many others who are. Also, the Shelter cartridges are very affordable compared to the others, and the sound is competitive with the best.