IMO, this was Nintendo testing the waters. I was one of the skeptical ones at first about the voice acting but I thought it came out decent at the end. Urbosa and Revali were my favorites, and although I liked the accent on Zelda, I agree with many that her voice was too low and lacked some emotion (at least compared to the Japanese version). The worst of the bunch was the Deku Tree. Still can't believe they used Revali's voice for that, WTF LOL???
Revali's english voice actor himself said he probably could've done a better job with his lines if he'd known his character's full story. Imagine how much better the performances would've been if the entire cast had known the whole story!