This debate is part of a larger discussion on the so called "Infrastrukturplan Luftfahrt" (Swiss infrastructure master plan for aviation).
At the moment there are quite a few stakeholders especially in the canton of Zurich who want to impose a mandatory legal ceiling on the number of take offs and landings at ZRH
The cantonal government in Zurich and the ferderal government in Berne are opposed to fixed ceilings while acknowledging the concerns of those who are affected by the noise which is major issue in densely populated Switzerland.
As the airport will soon reach its "natural" capacity limit, not putting a legal limit on the numbers of arrivals and departures would mean that the airport would have to be allowed to expand its capacity and that would mean changes to the current runway system.
While it is extremely unlikely that any such changes will be implemented in the next decade or two given the current political climate, it is nevertheless important that these long term options are being discussed now at all levels of government now, so that the airport will have have a clear legal and regulatory framework under which to plan its future.
Given the acquisition of LX
one can only hope that the severely strained relations between the canton of Zurich and the German Bundesland of Baden Würtemberg which have led to the problematic regulations under which the airport is currently operating will be mended in the future.