I've been through EMA three times this year and unless my experiences were not typical the process of getting through security had improved quite considerably.
Arrivals unfortunately can still be the shambles of old. If you arrive on a half full aircraft with no other aircraft arrivals it's ok but if you get two or three full 737s all arriving at the same time it is far from ok especially if it's raining.
I don't think there is any chance of an HS2 station serving the airport as Toton (the intended station to serve Derby and Nottingham) is only 6 miles away. There is a railway spur from the Sheet Stores freight loop planned to the northern boundary of the airport but this will be freight only to serve the envisaged industrial development.