The problem with routing being the most important is that it is hard to discern from playing the course. Not many of us can play a golf course and then sit down and think, well, here is how I would have taken that same piece of land and routed the holes.
Are there obvious issues that can be spotted (i.e. long walks from green to tee, etc.)? Yes.
Can a golfer subjectively say that the holes, "fit well together?" Yes.
However, I dont think that most non-GCA's can effectively comment on what changes should be made to the routing.
Therefore, I believe that Macro is the most important, however, from a ratings standpoint, I'm not sure the raters are able to legitimately determine the quality of the routing vis a vis the other routing options.
So, from a ratings standpoint, I think the micro and the quality of the holes, individually, is the most important.