It's hard for me to translate ancient Chinese with 100% accuracy, but here's what I've figured out so far:
The main offender is his war declaration line. It actually goes like this: "[Hard to comprehend]! I will lead a large army, destroy your temples, kill off your people, and capture the survivors! [not sure about the last part]".....yeah, definitely more than a simple "you must be destroyed"
His agenda disapproval line actually raises some questions. The voice line goes like this: "Look at all my vast territories and holy relics! And what does your kingdom have?..." This line implies that Qin is not impressed by the player's lack of wonders, yet his agenda works the other way around - he is pissed if you DO have a lot of wonders.
Can't say anything about his greeting, hard to hear it clearly over the video maker's voice.
Overall - really liking his lines so far! They avoided the mistakes they made with Wu, and not only used the proper language, but also found an actor with a voice strong enough to fit the image of an emperor.
Regardless of volume, it seems so far that the voice actor's delivery is reaaaally bland. Yes, there's a risk that "Would you be interested in a trade agreement with England?" is a more expressive line.