An interesting idea, but I fear that the area of the impeller, the macerating area where a drain plug is ideal, would disrupt the movement of sewage.
Maybe your system is different, but on my macerator, the end of the motor has a slit in it to use a screwdriver to free up things. Replacement macerators lack the opening to access the shaft of the motor, so I drill a hole as part of the installation process.
MANY PICTURES HERE. I also posted the replacement process
HERE.