Are you sure of "noise cancelling mic"? Noise cancelling is more about mics in different directions and defining a main one, like the iPhone with it's top, bottom (main), rear ones (still this only works when not in speakerphone, since then you can't define which the main one is).

Coupling mics together is more about get louder audio without increasing mic sensibility (what makes a better quality audio) and stereo effect. It's a tablet, it's like being always in speakerphone, after all.