Let's start with a clarification. Planning the work is not the same as the work of planning, or designing. Once a design has been given a client's approval in a conceptual or schematic phase, there are quite a number of tasks that need to be completed before the documents are considered done. One task is establishing a structural system. Another is performing a code analysis for occupancy, type of construction, location of rated walls, etc. One relatively new task concerns having an energy conservation plan for lighting as well as heating and cooling. We were surprised on the last job when the local AHJ decided that we needed to have an energy inspector on site as well.
Technology has had its effect as well. Not so much in the nature of the task itself, but when the task has to be completed. Back in the days of hand drafting one could show a generic wall of say, 6 inches width, and later label and dimension it as something else. Today the draftsman wants to know what that partition is as the project begins - and you just know he's going to draw it at 4-7/8" wide. Thing is, you have to have a pretty good grasp on your code analysis to know that you don't need a two hour rated wall here, otherwise you end up with a redraw.
I think most Architects would agree that if we draw it once and draw it right we have the best chance for a quality document. Those changes and redraws increase the chances of leaving something out, and thus leaving it wrong for the contractor to find. Not the best time to have your errors found.
Drawing it once and drawing it right also has to apply to consultants. If the Interior Designer is providing the ceiling design for a ballroom, it makes sense to take his work and reference it into the overall architectural plan. Why redraw it? Planning the work means that the ID drawing arrives in a condition to be used that way.
Planning the work also takes into account that design is an iterative process. A structural frame is designed early in the process, but is refined later by accomodations for HVAC equipment and shafts, wind bracing, and unique point loads such as for heavy light fixtures. If the planning was properly sequenced, these refinements are just that - refinements - not a re-examination of the entire grid.
The larger and more complicated a project is, the more important it is to plan the work. Start with the general systems, and work to the specific items. Network diagrams can be useful is showing the sequence of the work, which can then be adapted to a Gantt chart schedule showing when the work is to be completed. More planning at the beginning of a project will result in a more efficient use of personnel and reduced costs. If we can plan the building, why not plan how we document it?