captaintobe is right. there is no other requirement other than the 3 year factor. i wasnt asked atpl questions in my airline interview. the atpl subjects arent necessarily for you to gain knowledge for airline operations. they are merely a test of your intelligence and your ability to be able to cope with the information that you would have to in the airliners. however it isnt expected that too much of the theory would be remembered when going for the interviews, such as certain BRW's and different mach no.s in different conditions.
I agree with most of the comments already posted. I did them before my first job though and 5 yeays later obtained my airline job. Specific ATPL knowledge wasnt really looked at however (obviously) they did want passes in all the subjects!