Well, I would say it's an older program with some good stuff in it. I don't think it goes into enough detail about certain aspects though.
Since it won't cost you anything, take a look at the Driveline 8 week program that you can get from their site. It is a little more detailed as far as a progression to follow, and has links to videos that explain the various drills.
As for a velocity increase - nobody can honestly say. Some guys have big improvements quickly, some don't. Some take longer to improve. Some never improve for various reasons.
In a general sense, if you take a player that has never really worked out before and introduce any type of program you are bound to see some improvements.
I think the program you linked is lite on the exercises you can do to strengthen the rotator cuff, but the stretches are pretty good. I've had a torn rotator cuff, and from experience doing some stretches makes the shoulder feel a thousand times better. You can find some more exercises here... Thrower's 10 variation .