What slam is missing for the prime undisputed hardcourt not GOAT world #2 to complete the retirement slam?
Djokovic retired in RG 2005, RG 2006, Wimby 2007 and AO 2009. So USO is missing.
As for being the benefactor of retirements, he has had three players retire to him in USO and RG and one in AO.
All in all that's 7-4 in retirements. Rather a lot. Federer, with his longer career, has 4-0.