You are putting way too much emphasis on real estate. Space does not make the system a Phalcon or an Erieye. The same Phalcon radar and the associated hardware has been housed on 3 GF550s for the IDFAF. These are small commuter aircraft even smaller than the Pakistani SAAB 2000s. I am sure the Israelis have not cut corners on their own requirements by going with a much smaller platform than the one the IAF has picked for themselves in the form of IL-78s. So I do not buy this bigger = better argument. Now for certain roles like policing around the region, as you have mentioned, you may want more air crew comfort with more lavatories, bunk beds etc. and that can be had on larger aircraft, however that hardly makes for a qualitative superiority over a platform that has more limited space yet packs similar radar and ECM/ECCM capabilities.