The reason I think he shouldn't be chosen to portray James Bond is because contrary to how proponents THINK they are behaving, many want Idris Elba to be chosen purely on an ideological basis. You will find that these people have not watched James Bond, do not know the plots of any of the films and have not considered the ramifications of the character's ethnicity on central plot-lines.
It was observable with every recent Doctor Who recast "Should we have a Black Doctor?" "Should we have a female Doctor?" Both Doctor Who and James Bond are established series that are over 50 years old, it simply does not compute to change such basic variables. Already you see shots of historical Britain that appear to have been filmed in modern day East London full of ethnic diversity. Frankly such historical inaccuracy is poor cinema. Actors should either be chosen based on the necessity of historical appearance or based on their merit as an actor (depending on role requirements), not simply to appease bizarre racial quotas aimed at fulfilling racial representation which in reality discriminates against actors who may be of superior quality and of a nation's 'native' ethnicity. It really sets a foul precedent for other sections of society.
Frankly, Idris Elba is only a hot topic when it comes to James Bond because of unseen forces, generating progressiveness spouting hype aimed at overturning some sort of perceived old-fashioned rules. It reminds me of the childish 6th formers I studied with who made it their mission to choose the most rowdy and unpleasant boy in the school to be selected as 'head boy' just for the sake of it."Wouldn't it be MAD if we got a Black guy to be James Bond! Imagine what people would say! Oh it would be such a laugh, think of all the attention we would collectively get!"
All this nonsense has no place in an empirical society.