It's an admirable approach, and in many ways what all games should be working towards. However, we're not convinced they've nailed it yet. The action is certainly fierce - what DeLise describes as "Call Of Duty on crack" - but from what we saw, the non-scripted gameplay serves to highlight a number of predictable AI deficiencies.
In short, they're simply not smart enough. They flank, they take cover, they drive vehicles, but in no way do they feel like real people, with all the ingenuity and cunning that goes with that. AI simply isn't that advanced yet.
Admittedly, we've only played the first couple of levels, and the game isn't due out for another six months. But on present form we suspect Frontlines will still be perceived first and foremost as an online game. Luckily, with the multiplayer looking as impressive as it does, that may be no bad thing.