There were many lingua francas of which French was supposedly the first global lingua franca. That changed and it became English (from what I understand). We will probably see another language become the lingua franca, so my question is: should it be English? Are there better candidates out there? Why / why not?
Consistent spelling and pronunciations but even native speakers get pronouns for certain nouns wrong sometimes.
And as for German being consistent there are still situations like Umfahren (Drive around) and Umfahren (Run over) that are written the same but pronounced different.