First of all he hasn't been cast yet, he hasn't even interviewed yet so I don't know how people can say his audition went well or failed. His name is simply being thrown around.
There are still 3 more Daniel Craig bond movies yet to come out. Bond movies generally come out every two to four years, so Craigs last movie will be around 2020. So the new bond's first movie will be 2022, by then Idris Elba will be 50. Most likely too old to play Bond, though he could still pull it off, I would bet on the studio picking a younger actor.
As for Idris Elba's resume, anyone who has watched him knows he could pull of Bond. Luther alone shows his acting chops, but he was also very good in Rock'n'rolla and Pacific Rim. Also he's already pulled off a white character well in Hiemdall.
As for a black man playing Bond, I don't really have a problem with this. though there are plenty of excellent and if I must say better actors who are white that could step into the role. Ewan Mcgregor and James Mcavory are both actually Scottish, and more accomplished actors then Elba, I would rather the role went to one of them.
Sony would be much better off introducing Elba has 002, making him a complete badass in one of the upcoming films, and then giving him his own spin off movie.
Personally though I think the job is Tom Hardys to lose.