Has there been any word on whether or not they're going to have dual objective maps, or are they all going to be one attacker/defender?

I believe it's a one attacks and one defends thing. Not deviations.

If you mean multiple objective per map than yes.

I think he's asking if both teams are defending an objective while trying to secure the oppositions objective.

I thought this was the point to all A&D maps?

No, at the same time. Like in maps like Depot

all game modes wont neccessarily be A&D

It depends on what you consider Attack and Defense. I think both teams can switch combat roles when certain objectives have been completed.

Just an example:
The resistance has to steal documents and transfer them. They're obviously attacking at this point in the game.
Then they need to go to a command post and have someone standing near it for 2 minutes to transfer the documents. At this point the attackers will have to defend the command post position.

Combat roles can easily switch based on the map and objective design.

^this. but yeah i hope that there will be games like "see who can capture the command post first and hold it the longest" that would be very cool

Do you mean the same objective would go over to maps? As if you say you would only get half way through a mission and the map would change to do the other half? Cause that surely would not be a part of multi-player, maybe in single player that could happen...

no, he wants to know if there willl be game modes where both teams are attacking.

EDIT: i think

singleplayer=multiplayer
so what won't happen in multi, won't happen in single either

It was a type of gamemode back in RTCW/W:ET, where both teams had objectives to complete in each other's bases at the same time, and the side that completed it first won the map. Usually had a forward spawn point that was constantly fought over too.