Haha it's really not. DDA would be a wasted foreign player for Leinster and Snyman would be good if we can't renew Fardy's contract but we have two promising second rows primed to join Ryan next year. The world cup winner that would make sense to sign is tied to Toulouse for 5 years considering it seems to be against IRFU policy to have foreign talent starting in the front row or either half back position. South Africans are rarely good fits in Leinster anyway, Ollie le Roux and Richardt Strauss are the only ones who are remembered fondly, Ulster (religion) and Munster (presumably land and farming) are far better fits more often than not.
But, this is nothing short of a coup for an Irish province, you really have to go back about ten years to Pienaar, Elsom and De Villiers to find us signing an SH international who wasn't retired from international rugby. And it's a team Rassie was coaching less than two years ago who he provided with his replacement, and it's come just after South Africa have allowed the selection of players regardless of where they play their rugby.