My understanding of triaging is that it is mostly a crisis prevention strategy. If you are prone to getting bogged down on hard passages, or routinely run out of time with a few questions left, then it makes sence to spend the minute or two and figure out where the easy test points are and focus in on those so that the questions you don't get to are the ones you probably would be least sure of anyways. If you usually finish on time then triaging might not be a good use time better spent on the questions.
Secondly, I do a sort of abbreviated triage where I simply pass over anything that intimidates me or throws me for too big of a loop at first. This way I get to most of the simple questions while I'm still fresh. Then I usually have extra time so I return to the harder questions I left blank, with less stress because I already filled in 90% of the test section.
Also, mapping should not be wasting your time, it should be saving your time. I thought mapping was extraneous too, but then I realized mapping doesn't have to be as drawn out as how KAPLAN initially presents it. Heck, I'd say I map everything I read, only I keep the map in my head instead of writing it down. This might work for you or you might already be doing this, but I imagine a lot of people in KAPLAN may not be able to keep the passage maps straight w/o writing it down, so KAPLAN says write it down.