Besides which, an accent isn't genetic, it's sociological. Especially if you are a child, accents are picked up from the environment you are in, but adults will have accent changes if they are outside of their native environments long enough too--Mel Gibson threatening to kill his wife doesn't anything like the Mel Gibson in Road Warrior. Boba Fett shouldn't sound like his father unless he was living in the Star Wars equivalent of New Zealand in between Attack of the Clones and Empire Strikes Back.

Its the perfect example of someone perceiving a hole that doesn't exist and then creating a problem in the films through the "fix" when nothing needed to be changed in the first place.