Germany was doing a decent job of this in Tanzania and Cameroon. I could see this evolving, especially with the Askari's support in WWII. (Germans win and give the Askari equal status?).
1914 is far too early to estimate the outcome of a surviving German colonial empire, given the host of political transformations which occurred in the French and British empires in the following decades. Also while they invested a vast amount of money into their colonies, and had in some areas effective education, I've heard nothing about their political administration being even vaguely progressive, outside of German Samoa.
The Germans treated the Askaris well after the Great War, but that had important political objectives in mind, aiming to attempt to show that they weren't uniquely evil in colonialism as the British portrayed them as, the black legend of German colonialism (true to some extent in Africa, the Germans were the only ones to have done a genocide there, with butchering a hundred thousand people in Namibia, plus the hundreds of thousands they murdered in Tanzania). If there wasn't that political objective, I'd expect that they would be exactly like the French and British - lots of promises, and not much actual work on the ground.
France tried to do this, but failed. Mostly they were just too late to get it to work effectively.
In addition to being too late, there is also the severe problem of that it was a negative cycle which steadily undermined French colonial ambitions. The French hope was to update colonialism and bind French Africa more tightly into the colonial system, utilizing assimilation as the supposed goal, and doing it with the drain on metropolitan resources being limited. These were incompatible. Assimilation worked at keeping African politicians in line, but it fundamentally introduced the corollary that Africans would have equal status, and equal treatment, as the French. This undermines political control of course, and so for example French colonial authorities were less able to suppress strikes vis-a-vis the pre-war period, but even more importantly it led to the political campaign on the part of African civil servants to link their pay scales to that of Metropolitan civil servants. This couldn't happen in British colonies since they weren't part of the same administrative unit as Britain, they were part of the Empire, but they weren't Greater Britain, unlike in France. The same with workers, where unions in Africa wanted the linkage with unions back in France so they could claim that they were pressing for the same pay scale. Costs steadily escalated and grew and paying the costs of civil servants was crippling for financial projections. Ultimately the French decided to make local territorial assemblies responsible for the funding of the civil servants, and while that was an expansion of their power, the French were freed of the weight of having to pay for them... promptly, most of the territorial assemblies cut civil servant pay.
Which is the problem economically, in that it isn't sustainable, unless if Africa has a lot higher per capita income, for Europeans, except on a very small scale, to fund their colonies to the extent that they are able to make real the idea that the two regions are part of the same nation. The French, who have the largest remaining colonial empire, can do it, but it costs billions of euros every year in transfer payments overseas, and there are "just" a few million people in their colonies. Compared to the rest of their colonial empire.... the cost is not sustainable. Assimilation made for a useful rhetoric which helped keep the colonies in check longer than they would have been otherwise, but it was never a practical long term plan, and ultimately the French recognized it when the costs of this strategy started outweighing the benefits.
And that's only dealing with it economically. There was enough fear that France was being converted into a colony of her colonies, and that was with the colonies having a dramatically reduced representation in the French parliament than they would be entitled to have on their population level. I made a joke about that a while ago in another thread, that giving colonized people rights is all fun and games until black and asian people start voting in elections affecting
you, and it still sums up the problems with political assimilation into the metropole.
End of Empire in French West Africa by Tony Chafer is a good book on the subject.