Canelo isn't going to diffuse Benavidez' attack with stationary feet and pure head movement; David will simply throw in feints, alter his attack upstairs and downstairs, and alter the speed/power in his punches. Literally everything he couldn't do against Plant because Caleb wouldn't stand still. If Canelo spends the fight trying to offset Benavidez' attack, he'll never get going on his own attack. He'll have to take some real damage in order to get the job done.
Even in moving up in weight, Canelo has been able to play the stalker and walk his opponents down, controlling range and setting up his heavy looping counters. He would not have that luxury here, and it would be interesting to see Canelo trying to fight off of the back foot.