I'm not sure what your purpose was for posting this. I think it's obvious you need to do something before you end up with diesel in your bilge. And, using an emergency repair (ie switching the hoses) long-term probably is the best thing to do.
My boat's original diesel tank was also aluminum, built in 1980 and put into service in 1981. Two years ago it started leaking. I pulled the tank and put JB Weld over the leak and along any spot I thought needed it (inside and outside). One year later, it sprung another leak in a new place. I investigated many alternatives. I ended up having a stainless steel tank made.
I'd say your tank is near the end of its life expectancy. But, it all depends upon how well the system has been cared for (frequent fuel polishing, additives to remove moisture, quality of fuel, humidity levels, etc.).
The answer to your question: It's your choice.
Skipper, J/36 "Zero Tolerance"