I agree that it this book has no place in the Heresy series. With a few minor alterations it'd work as a Space Marines Battle novel just fine.
The Iron Hands being caricatures is not exclusive to this book though. There are barely any members of this Chapter/Legion that come to my mind whose character extends beyond "The flesh is weak!".
Why did it even need to be made?
Apparently it adds 0 to the storyline and just focuses on random space marines fighting dinosaurs. It hurts the integrity of the IP.