I liked how Marvel allowed each of their franchises to breathe separately before bringing them together in one large film (i.e. Avengers). I think the idea of bringing in Batman well before he has his own film within this uni is jumping the gun by a large margin.

CLARK: No. I'm just worried I'm a jinx.
JONATHAN: A jinx?
CLARK: Yeah. Let's face it, ever since she's known me, Lois's been kidnapped, frozen, pushed off buildings, almost stabbed, poisoned, buried alive and who knows what else, and it's all because of me.
-"Contact" (You're not her jinx, you're her blessing.)