There is one problem with debt relief:
IT DOES NOTHING TO PREVENT FUTURE DEBTS FROM PILING UP!
If Niger, Botswana, Sierra Leone and other nations needed to borrow money in the past, oragree to some IMF or World Bank treaty to recieve aid, what makes you think they won't start accumulating debts that will get them right back to where they just were?
Give a man a fish and he eats for one night. Teach a man to fish and he can feed himself forever.
This kind of band-aid from big nations does help in the mean time, but it also means they're less likely to go about doing things liek provide cheaper medicine, provide major infrastructure improvement projects like irrigation, better roads, etc.
We have forgiven major debts in the past. Debt relief isn't anything new. Like I said, many nations just pile up new debts and the actual people who are struggling day to day don't get the help THEY need from the US and other G-8 countries. Half these debts and a great deal of the disparity is because of corrupt government officials rent-seeking and skeeving off the top for themselves and their cronies. These are also the people debt relief helps the most, the government officials and big businesses of the nation.
Rather than forgive all debtors, how about establishing a way to see which nations' leaders deserve the relief and which ones will just heave a sigh of relief and then put the $ they were supposed to pay in debts right into their own pockets?