On Youtube, "Mr H Reviews"(I know nothing of his track record or anything else) is saying a "source" has seen a rough cut of the trailer, without any special effects for the most part. Hard to believe this early, the "source" does mention the Lois/Superman rising in the air scene, some of Lex, Lois, and Jimmy. This "source" also mentions a questionnaire about Krypto and if Cavill should come back. The Cavill bit to me is a dead give away this may not be legit.
This Mr H is highly impressed with his own credentials, though I am skeptical. Don't know much about the film process, so take it for what it is worth.