Well, you would think, what with Batman being around for a while.
However. I don't think he should have anybody around in this movie.
What I would like this movie to establish, is Bruce learning to really trust someone, to have his back. Someone other than Alfred or Gordon.
He should come into this from a life of nothing but routine. He does this by day, he does that by night. He has no life, he has no real friends. He spends his day living a uninteresting facade as Bruce Wayne. He spends his nights doing detective work, fighting criminals and getting inside the minds of them. All this for the past 10-15 years of his career. It's warped him.
It's warped his sense of complete trust to anybody he doesn't know personally as truly genuine.
It's warped him in a sense, that he can only really rely on himself and not even Alfred and Gordon's friendships are strong enough to change his ideas on it.
It's been in that unshakeable routine for years.
Then Superman comes along. And in Bruce's mind, having dealt with the superpowered criminals of Gotham for all the years, someone with powers like that, cannot be trusted, no matter what saintly image he's trying to present. Bruce knows well enough not to trust someone like that.
And even if Bruce and Lex Luthor do confide in each other that they have the same feelings regarding Superman...Bruce knows best to not even trust Lex either...
But eventually, Superman should actually change Batman. Changes him that he begins to be more open and less of a loner, that for the first time, he was genuinely wrong about someone.
It breaks his routine. Enough to allow Robin, Nightwing and Batgirl into his life.