It isn't a rule, but wouldn't it be nice to have an actual african artist make the song for the first african World Cup? You know some actual piece of SA culture, not a "feature" that hardly does anything besides showing up in the music video. Although, after watching the video I'm not even sure who the members of Freshlyground actually are?
This is by the way the actual song from Cameroon that Shakira sampled hers off without permission of the copyright holders and hasn't ever even crediting the original artist and claimed on her website that it was a completely new song made by herself.
The reception of south africans for this song was also rather negative and I can understand that. They were denied the chance to host the WC and thus showcase something of themselves. The reason why the World Cup is so popular besides the sportive aspect is the whole "culture clash", even the fucking vuvuzelas that we all hated did kinda add to the charme of that tournament. If you're going to host a WC in South Aftica, then make the whole theme fitting, instead of awarding it to a random artist of a completely different continent, who's illegally sampling a WW2 army anthem of a completely different country, mix in some english lyrics that your average X Factor quarterfinalist could write and shake her hips a little. I found the whole thing just weird and from a musical perspective I thought the result was a rather boring song but that's just subjective.