It is possible that a merger this size could have an effect on the commodities markets we buy our ingredients through. Probably not at this point but it could happen down the road if the big boys move all their grain and hop production in-house. It might not be worth the farmers time to supply the craft market.
I agree with most people on here that this size merger would have a hard time getting approval in Europe. Here in the US it will just take a few more contributions to the correct campaigns but that another matter.