It sounds right. That's the important thing.
I think Mark Hamill should be extraordinarily proud as an actor - as good as others have been at the Joker (Jack Nicholson, Heath Ledger, John DiMaggio, etc) whenever anybody thinks about the character anymore we hear THAT VOICE and THAT LAUGH. He's put an indelible mark on the mythos by defining for a generation what the Joker should SOUND like.
And Troy Baker can definitely do THAT VOICE and THAT LAUGH. So it's all good.