I think that CMFB is a must in OPAMP's with active loads. Coz when u r using active loads, u can't define a certain output common mode level. While if u r using load resistors, it's easy to define ur common mode level.
Also u may use it with fully differential OPAMP's and single ended ones. For the fully differential case, u will sense the common mode voltages of both output terminals, then compare them to the needed common mode level, u will use to resistors or two caps (to avoid loading) to sense both voltages. While for the single ended case u will sense only the voltage of one side, which is easier.
Take care from the CMFB and the stability issues