It's not a bad change, in spirit. Orbital Strike was comically overpowered. Drop it on any stationary boss and you do gigantic damage with minimal effort. With that said, there needs to be a talent near the top of the engineering tree which gives most of that damage back to OS.
It's a pretty awful change in spirit. The ability has been neutered in all respects. Not only it's usefulness, but its very feel.
Also I fail to see how that's particularly overpowered. There are a lot of classes that can drop gigantic damage on a boss with minimal effort.