I personally don't think anything needs to be added to the cover. It is already funny as it is, just the idea of Al as a dictator. Also, MandALtory Fun just seems more complicated to say, and really doesn't flow, so I am choosing Mandatory Fun
However seeing the fit of rage of that Jon would be in if the title was MandALtory Fun would be funniest, since he still seems to want to make a big deal about this.
The times Al has used that in a title, it felt organic, like it didn't totally crowd the rest of the title. MandAltory is just so forced and unnatural when compared to the other times it was used.
I think the most common speculation for the title was "RevAlution," which is also just as awkward, if you ask me.
Mandatory Fun is good. Alpocalypse and Alapalooza (the only times he actually snuck Al in the title, aside from the first album) both worked because they weren't trying desperately to fit in an Al pun; both of those titles roll off the tongue without making it sound super-forced.