Not a bad idea. With the camera technology we have today, it is easy to call balls and strikes from the booth. You would still have to have a home plate umpire to call plays at the plate though.
There is no need for any umpires at all! Plays at the plate, just like close plays at the bases can be appealed to the video gods, so why bother at all, just have a video umpire in the booth decide all the plays, and simply indicate if the player is safe or out by lighting either a green or red light on the scoreboard!