Big maps can be a big plus, or a big problem. DICE did a great job with Battlefield: Bad Company 2 in my opinion, and therefore that get some of my trust when it comes to this. Nonetheless, it's easy for big maps to make a multiplayer experience boring.
I'm not a gamer that requires constant action by any means, but when I'm in multiplayer, I expect to have some interaction with other gamers. If I'm lost at some random point in a huge map, I'm probably going to leave the lobby out of boredom.
With the addition of vehicles, which I'm sure there will be given this is a Battlefield title, that issue should be eliminated to an extent. I don't want to have to rely on vehicle transport, however, to get from point A to point B.
This news is exciting, definitely, let's just hope DICE knows what they're doing.