No. The transmitters calculate signals such that constructive/destructive interference will combine to form a strong, clean signal in the precise location where the device is.
> The more antennas you have, the cleaner you can keep the beam and minimize constructive interference happening in the wrong places.
Beyond three antennas surrounding a given device, this just isn't true -- more antennas don't produce a proportional increase in performance to compensate for the increased computation workload.
Yes, true, but the entire system becomes more complex for a small improvement in performance. Also, most of the theoretical work in a scheme like this would focus on the least common denominator, which is three antennas.
Interestingly, for a roughly circular array of antennas, you end up with concentric rings of high signal strength as you approach the midpoint of the array. So even the thesis that you've eliminated unused hot spots breaks down in some cases.
Here's my diagram for three phase-controlled antennas (the blue dots):
http://i.imgur.com/tyyVh0j.png
The wavelengths in this diagram are longer than for a cell system, it's just to show how this idea works. Buy adjusting the phase at each antenna, you can move the high-strength lobes around to match up with the location of a given device.