I have been flying a lot from Stansted recently. I have to say that they have security well under control in the morning and I generally get through within about 15 minutes of arriving in the terminal.
The terminal drop off however is a different matter. I believe they have been looking at different options to try to sort the issue out but the taxi drivers tell me traffic is backed up to the A120 junction from about 04:30 to 07:00 the airport are apparently looking for any good ideas to resolve it so if you have one please let them know.