Simply that lots of people, ATCO and ATSA, are ready to critisize but very very few are actually willing to make positive contributions.
Complaining is easy, NAS IS %^$£*g complex and so will iTEC be by the time it (SACTA) has been modded to manage the London FIR, so any help is always appreciated! Most ATC staff do not understand just what FDP systems do, they use it.
Much better that complaining
Take PAC, MAC, REV. Is there a requirement for these? Not at LACC apparently and not at all for MAC and REV!!! If the IS a requirement then say so.