I won't disagree that Revit is more costly or that there has been a loss of layout/drafting expertise. Too many people doing layout seem to be no more than line jockeys and just put lines down to indicate piping wherever they want to without really thinking about coordination with structural or the othe MEP drafters. The common rationale that I have heard is it will be worked out in the field or we will catch it on the coordination drawings. To me, that is too late. Again, it is cheaper to catch it before bid than after.
I like revit because I have some struggles seeing things in 3d when I look at a drawing. With revit, I can cut a section(without the extra drawing that 2d requires) and see where everything is at. I have used this to determine where my run of sloped piping has to start (tight to structure), where I have to drop the pipe to miss a beam or a duct or something else and the neferious villain of sloped piping - the ceiling. I can tell if what I am designing will work or if I have to call the architect and ask him to lower the ceiling. Now, granted, all these things can be done with 2D cadd, but you have to draw it out or you have to calculate it yourself - and there is nothing wrong with that. But with revit, I can set the slope on my pipe and do it all automatically.
In the long run, that is good. But it does require that the person doing the drafting understand what is going on and not just be somebody who puts in lines where the engineer wants them to be. With Revit, there cannot be drafters per se. They have to be designers with some knowledge of what is going on.
Revit will likely mean the end of the engineer handing sheets with penciled in markups and the drafter just putting them in. I don't know if that is progress, but it seems to be the direction things are going.
Revit will also require engineers to make sure it fits. They will look pretty foolish if the architect/construction manager/contractor cuts a view or section and sees the piping below the ceiling or through a duct.
My company hasn't totally bought into it yet. We want to see if the extra cost and the extra up design time/fee pays back in the end. I think it will - once the bugs get worked out.