If you removed Ryanair and Easyjet movements I think variety of remaining operators is still good. There is always something unusual and adhoc to see each day, particularly on Northside. It's just mentally filtering them out from all the usual stuff, which in the "old" days didn't need filtering. Airports in the UK have aircraft which are regulars to them but can be very rare elsewhere. Where else would you see two or three Eos and Maxjets on the ground at the same time, and for that matter nearly 40 Ryanair B738's (albeit between midnight and 6am!).