I also hated the opening of the film. He uses the Terminator Arrival Trope (naked until we find clothes) that's used in the other films, but he doesn't keep the style of these scenes consistent with how Cameron does it. If I recall correctly, once a person or machine arrives from the future, there are no cutaways to other stories until that person acquires the clothes/weapons. If Mostow is going to imitate the style of the other two films he should actually study them.
That is one of the films big failings:
In T2, Cameron took his time to build up the suspense, it takes at least a good 40 minutes (I think, I only watch the extended cut anymore) for both Terminator's to finally meet.
And what I love even more about that, is that Cameron plays it so we are not sure who is the good Terminator and who is the evil Terminator. OK, OK, so it wasn't a huge secret before the movie came out, thanks to the marketing and such. It is played up that way, and I love that.