I can only agree regarding the international arrivals at T2. There are only four desks for passport control (not all manned) and 1 baggage belt! One full KLM 738 is enough to create congestion there, with PAX queuing all the way up to the gate! So you can imagine the effect of, say, 3 Ryanair 738s simultaneously...
Regarding maintenance hangars on the western apron, nobody's mentioned the small issue of planning application. A few years ago Maersk Air Ltd. applied to have one maintenance hangar built for its 735s and CRJ200s. After over a year, the planning application process was still ongoing, with plenty of Sheldon residents up in arms against the project (even though a high berm like the one by the fire station would have been built to limit noise). By the time Maersk had become Duo Airways, then gone bust, there was still no sign of the hangar!
Food for thought...