Well, I think there's firstly some difference of culture that might exist between the resident of New Orleans and the Acadians: this was substanital enough to result in the formation of 'Cajun' culture OTL. The former would be accustomed to the more sub-tropical climate, disease, heat to say nothing of having greater knowledge of the crops (rice, indigo, sugar) and agricultural techniques suited to Louisiana.
Secondly, how does the greater Franchophone population affect Spanish rule of New Orleans and Louisiana? Does it result in greater resentment? Might the Acadians decide to take their chances in the Spanish frontier and perhaps settle parts of then Spanish Texas to retain their communal identity?
I have a hard time figuring how you'd manage to concentrate Acadian settlement in Lousinianna and New Orleans more than OTL, unless you actually have France transfer the population in 1713 to Louisiana. Perhaps an enterprising French governor in New Orleans offers the Acadians a good deal in Louisiana and they prefer to go there, rather than uproot to Quebec or live under the British.
In any case, the greater concentration and population of Francophones is bound to create some difference. Firstly, I wonder if it might compromise Napoleon's willingness to simply sell the entirety of Louisiana to the USA in 1802. It probably doesn't -- despite all his desire for an American empire, he still subordinated them OTL to his desire for a European empire. OTL the collapse of the Peace of Amiens meant he couldn't retain Louisiana; if we're going with low butterflies (and if we don't even the rise of Napoleon is suspect), then he probably can't keep it. If he does, then the USA might end up at war with France for the territory.
Secondly, does the increased Francophone population lead to concern in the USA about purchasing Louisianna. OTL Jefferson was so concerned about the potential "defects" in Louisianan and Cajun culture that he concocted a scheme that would submit the territory to a relatively dictatorial government in order to educate the inhabitatants in proper culture. It was quickly abandoned OTL, but may gain more purchase TTL: if Lousianna really has as large a population as you project, then at least the OTL state (which interestingly was orginially organized as the Territory of Orleans) might have enough people to qualify as a state almost imediately. If that's true, though, then I'd imagine they might start to object about being unilateraly transfered among so many different countries. Perhaps they might revolt from their overlords and attempt to set up their own republic before acquisition by the USA -- a not insignificant threat to the US given the hypothetical upstart's control of the Mississippi.
Additionally, there's the question of what the new Louisiannan culture looks like: does it embrace plantation style agriculture and slavery or does it prefer small-holding instead? This is crucial to determine the balance of interests if this territory joins the USA.