Yeah I've never liked the idea of changing a character's ethnicity just to appeal to the mass audience. I think legacy is sacred and by messing with it, you piss off a lot of people.
Don't get me wrong, I'm all for a big iconic role led by a black actor, but it pisses me off if they have to take a "white role" and change it. Movies like Black Panther is a step in the right direction because that is a "black role" and it's a great one, and I'm sure it will be a really good movie as well. I don't think there's anything weird with wanting certain roles to remain somewhat the same. Could you imagine the outcry if they made a new Shaft movie and cast a white guy as Shaft? There needs to be more big roles for not just black people, but also other minorities (like Asians) but to me, changing an existing "white role" and shove in a minority is not gonna solve that problem, and if anything it's only gonna cause more turbulence.
If they came out tomorrow and said that Idris Elba was the new Bond though, I would be fine with it. He's a really good actor and I think he has the chops to pull it off. But they could just as easily make a great original spy movie and cast Elba and create a world of their own, and it could work just as well.