How does an eILS improve throughput (for the A380)?
The bigger the aircraft, the more disturbance it creates to the ILS signal while moving on the runway (or TWY). Therefore airports have static and dynamic ILS sensitive areas to assure the validity of ILS signal. The eILS has smaller dynamic localizer sensitive areas, and aircraft (A380 in this case) will vacate this area in less time, enabling reduced separation and increasing throughput.

A little something about ILS critical and sensitive areas: Determination of ILS Critical and Sensitive Areas - icasc (.pps)