A washing machine appliance or drive assembly, as provided herein, may include an agitator drive shaft and a motor. The agitator drive shaft may extend along a drive axis from a first end to a second end defang a mounting portion about the drive axis. The motor may be operably connected to the agitator drive shaft to drive rotation thereof. The motor may include a rotor and a stator. The rotor may be fixed to the agitator drive shaft at the second end. The rotor may define a central aperture along the drive axis. The central aperture may define an interior profile complementary to the mounting portion of the agitator drive shaft. The stator may be rotationally fixed and positioned radially inward from the rotor.