To argue the other side:
In the link you describe, it says that "It is easy to understand how a senior manager might read this PowerPoint slide and not realize that it addresses a life-threatening situation,''... but would a senior manager have read a 20 page thick technical assessment? Would that have truly been a better medium? If you can't get a point across in a 30-second slide with less than 100 words, why would I believe you could get it across in 1000 words?
If the engineers failed to convey their point appropriately, they failed to master the art of being concise. That's not powerpoint's failure - it's their failure to be able to convey the material. (Thats not to say that powerpoint documents are not often terrible)
As an MC, I'm surprised to see you chose a whitepaper over a deck. Do clients actually ask for this? I've never seen a CEO say "Ok, type up all the analysis, all the metrics, interview details, primary and secondary arguments, issues, concerns, sources and other assumptions and provide me with a fully documented thesis on the issue that I can read over the course of a few hours" Rather, I see clients say, "Look, I trust you've done the analysis, show me the basic steps you took to get there, give me the upshot, and if my staff have questions I'll direct them to you."
Thats 98% of the art of consulting as I know it - condensing large amounts of data into clearly demonstrated, well researched, easily digested recommendations. The reason the consulting firms (bain, bcg, mck, deloitte, etc) have case interviews with lots of irrelevant detail is to see if you have the ability to look at information, extract the important facts and present a cogent argument.