Unless there is a Revolution in Germany and the whole country is no longer ruled by the Prussian military, i don't think that the Alsatian would have develloped a german identity (ok maybe after 100 years of occupation).
Just a note, I don't think it matters if a "German" identity is developed by the Alsatians, they speak a related language to German. What matters is if they develop an attachment to the German nation, not ethnicity. It would have helped if the area had actual autonomy like in the other German states within the Empire.
I didn't know occupation can last that long.