I never thought of a tandem as a touring bike before. Is it in fact a touring intended bike? Seems to me one issue with touring is fitting enough luggage on board. With a tandem you haven't really increased the luggage volume capacity over that of a single, while admittedly you may have marginally increased the per capita luggage weight capacity. Next issue is durability. Two fairly svelte riders plus full touring gear must be ~400lb; are there wheels and drivetrains engineered for this load over the long distance? Third, brakes! Fourth, being a stoker and "touring" don't really seem to go together, do they?
This is just my curiosity, not criticism, per se!