I always thought the fixed rostering pattern is what keeps people at Easyjet!
In my previous life (Not Easyjet) I was in Ops Control / Crewing and also did a stint rostering.
Yes drag and dropping does happen but sometimes it is the only way to get the rosters out on time. There isn't time to look at crews as individuals unfortunatly.
Computers do do rosters, but you always need human intervention, there is training to consider, sickness. Even when you have run the roster with the computer someone comes up and says someone has gone long term sick, or needs additional training. So this not only affects the individual roster but often 10 more people as things are moved around to cover the duties. You won't get rid of rostering officers unfortunatly!!
It would have been nice to be able to be bit more personal but this is the real world!