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?
Of course that is a limitation.
While we’re at it we could also mention that like with a lot of things you can control, this is also a thing you don’t have absolute control over. But with majority consensus you can teach whatever language and really focus a lot of hours on it, and it’s significantly more likely to be a successful widely spoken language that serves as the lingua franca.