I think to allow use to add customed type column like omnioutliner should be better for organize data. I use omnioutliner pop-up list to control the status. If we get a pop-up list with customed icons( show the traffic light, red, yellow & green), it will be prefect to project manager too. ;D
Customization of displayed columns will come in 1.8 but no user-definied columns yet.