You can drive a car by looking in the rear view mirror as long as nothing is ahead of you. Not enough software professionals are engaged in forward thinking.
Systems are going to get a lot more sophisticated.
Not all smart people work at Sun Microsystems.
Interleaf is very nice. I expect there to be a lot of competition for programs like that.
I think multiple levels of undo would be wonderful, too.
The reason I use ed is that I don't want to lose what's on the screen.