I have had similar concerns about his approach with this witness. I don't think you're overreacting or coming out of left field.
But, I do not believe his aggressive approach with this witness will cost him the trial. Not by a long shot. The case against jodi arias is too strong, IMO. In other words, even if the jury dislikes his style of questioning in relation to this witness, i don;t believe it would cause them to disregard the case he has made against the defendant or the terrific dismantling of their witnesses.
And speaking of such, watching this cross (as I am right now), I can see how he has completely put this witness on the defensive, so much so that instead of just answering the questions and letting Ms. Wilmott clear any issues up on re-direct, she must try to anticipate and guess the hidden meaning behind each question and not allow him to make the point she thinks he's trying to. And her refusal to answer his questions in a straight forward manner, as she contorts to try to prevent him from scoring any point, no matter how small, makes her lose all credibility.
So while I have had deep concerns about his style with this defendant, in the end, I think he is achieving the objective he wanted.