Maybe I'm wrong, but it seems to me that the biggest DLC that this game will have come out with so far would make sense if it were announced at E3 Expo. I haven't been following any of this until a few minutes ago, but it would make sense. And based on what everyone is saying that it is expected for June, I would not be surprised if this were the case especially considering that E3 Expo is going to be held June 5-7.
It would be nice, but there's no actual sources behind what I'm saying. It is purely speculation.