I've just recently found this to be an essential item. I have a building under construction right now that has two concrete tilt-wall panels that are 1'-0" too high because the dimension didn't update, and who can remember to check every single dimension every time you issue a drawing?
One of the key components of documenting with any virtual building/BIM software is the automation of tags, detail numbers, etc., and it seems that dimensions should be right there with them. The "work around" of using additional text entities negates the dynamic nature of a "live" dimension. If we make a building taller, or stretch a window, then we have to remember to go and move the additional text, which is opposite of the automated nature of BIM software.
I think all of the suggestions in this discussion are valid, and I'm sure most would find uses for all of them. In my opinion, this should be in the "bug" area, and not here as a "whish list" item.