An old proverb: "some like the mother, some like the daughter". If you like the AVR and it is the right chip for your application, go ahead and use it. If you do not want to use the AVR, use something else. Asking the true an proven '51 to become an AVR does not make sense. In my humble opinion. the AVR serves one purpose only, namely to give Atmel a proprietary design

Have fun,

Erik