Seems potentially cool, but I'm not really getting why they'd bother calling this "Battlefield" other than for marketing reasons. That basically is the reason, but still, I associate "Battlefield" games with big wide open battlefields with tons of vehicles, not cops and robbers.
Battlefield has always been vehicular warfare with infantry. Whether it's on a small map or a large map, it doesn't matter, Battlefield is basically the only good game that does vehicular warfare correct.
BF2 PC started seeing a bit smaller maps with 16 players for 8v8 action, it was great in my opinion.
Then if you look at BF4, they've got even smaller scale modes like TDM, the defuse game mode (which I think needs a lot of work), small scale domination, etc.
If they do this counter-terrorist vs terrorists thing right, they could have another unique game on their hands. But it needs to tie in the Battlefield core like the class-based gameplay and the squads, vehicles, etc.
