WBC championship
WBO championship
then a collection of various organisations all put together to make one solid cast iron championship belt

Mandatorys considered non-optional only if theyre is a clear case for a fighter to choose to fight in a more lucrative fight ie:vitali klitschko doesnt lose his title for opting to fight david haye rather than a lesser mandatory opponent.

oh and bring back the super-heavyweight division so we can have freaks like valuev out of the real division