Back to my argument: the Scimitar still pretty big and it can't change course that fast (example: can't get out of the way of the "E" during the collision) and phasers, even if not lightspeed, are much faster. Its position and most course information is revealed when launching any weapon, so its not like you don't have data.
I'm also surprised that after with all of the "fight a cloaked ship" scenarios Starfleet could have planned for, there's no setting on the torpedoes to follow an enemy's impulse plasma (sorry, wrong movie), or better yet get informed by a phaser "tag" and change course. This latter capability we could do with a drone today with little difficulty.
I know, i know, they wanted a cool crash scene.