Is it different than the game? Yes. Lost that cel shading for more realistic and Murray got a heck of a redesign there.
Could it still be cool? Sure. Looks like good 'coony action in the trailer.
Same voices? Sounds like Bentley but Sly is different. And since Carmelita has had a different voice in every video game, it's not like consistency is a hallmark of the series. ;)
You can also follow the project on Twitter: @slycoopermovie
Will it be good? Can't say, but the makers are also involved in adapting Ratchet & Clank (another game series I like) for a 2015 release, so we'll have some forecasting...