Couldnt agree with you more - the whole bloody world should issue the same licence!!
Your problem however will not be one of licence but one of work permit. You will not be able to work in SA as a foreigner. However since most contract companies work outside the borders of South Africa some of them will be happy to employ you elsewhere on the dark continent with your validation flyin ZS ( south african) registered aircraft - untill the SA CAA decides to not renew it in a year or three - at which time you will have to sit the exams or leave the job.
Some contract co's register their machines elsewhere - Ghana, Swaziland and a few others come to mind - and should you get employed on those you will need the validations from those countries. Not to be confused with the work permit which will be for the country you actually fly in.
So its entirely possible to work for a South African operator and fly a Ghanain regsistered a/c on a Ghana validation of your Aussie licence in Sudan with a work permit issued by some Sudanese official!!