A lot of people are trashing this dub before it's even really gotten out of the gate. I watched it, and while it was clear it had been Americanized, it came out pretty well. Ben Diskin is good as Stitch, I don't think people are giving him enough credit for that. The other voices are okay, I'm sure they will improve. Eden Riegel was very good as Yuna, she made her sound sweet without being annoying, which is a hard thing for voice actresses to balance. They also left in some Japanese vocabulary in order to give the show a certain flavor, so it's not like Nimoy took an axe to this thing and tried to turn it into something it's not.
By the way, from the credits, it would seem that Jamie Simone (of Naruto fame) is doing the voice direction, and VAs like Derek Stephen Prince, Stephanie Sheh, and Laura Bailey all have roles on this show. If they wanted Blum, I'm sure they could have easily called him in (and may yet do so), but they made a creative decision that I think is working out well. I'd would definately like to see more.