As the Cisco description makes clear, this is not about them "getting directional" - it is about using the combined signals to/from multiple antennas to produce a more consistent signal that is less affected by multipath fading. The antennas used at the access point will have spatial separation, but in most implementations would be omnidirectional (just as in 802.11n MIMO deployments). In fact Cisco emphasise the benefits of this approach over a directional/beamforming solution.

Nevertheless this does not overcome three other fundamental issues associated with poor throughput in microcellular Wi-Fi, which in my experience generally have a greater impact on enterprise wireless performance - non-optimal AP selection by clients, co-channel interference and packet loss during roaming. All these issues are solved in Meru Networks' architecture.