Even the ones that are bigger were explained in pretty good time. Take Dunkelzahn's death, for instance. It didn't matter exactly how he died to use any of the game ideas in Portfolio of a Dragon. Whereas (say) not understanding what the "EMPs" are in Cutting Black absolutely does put a crimp in most GM's abilities to use the material, I would say. And if you did care how the big D bought it: well, the Dragonheart novels explained all the backstory, and the first of those was published (IIRC) just a few months after the sourcebook.
...I'm not sure any sourcebook actually clearly explains Dunkelzahn's death, but there certainly wasn't one within years of his death occurring. Within years. Literally the biggest event in UCAS history, and they only gave players hints and contradicting rumors about what happened. I don't really care if it was explained in a (pretty crappy) trilogy of novels. Shadowrun novels
are not sourcebooks. Neither do I recall FASA advertising "hey, if you want the definitive explanation, read
this". I didn't personally find out for about a decade that's what the Dragonheart Saga was about.
It didn't matter exactly how he died to use any of the game ideas in Portfolio of a Dragon. Whereas (say) not understanding what the "EMPs" are in Cutting Black absolutely does put a crimp in most GM's abilities to use the material, I would say.
First, I'd like to point out that comparing your difficulties with actively using a major event in your campaign (EMPs) is different from using the fallout of a major event (Dunkelzahn's will). The proper comparison would either be trying to using Dunkelzahn's assassination, which was presented with a comparable amount of questions, or comparing the
fallout of Cutting Black with D's Will. The Big D biting it left a giant rift between the physical and astral planes right in the middle of DC...why? What was it? Where did it come from? What could it do? Was it going to grow? Could things come out of it? What are the consequences of its existence? And of course, who killed him anyway?
That said, Portfolio of a Dragon is one of my very favorite gaming supplements ever, just under The Book of Exalted Deeds. However, I think you're willfully ignoring some pretty major things mentioned in it, that certainly weren't addressed quickly thereafter that seemed like pretty major plot threads. What are the Keys of Power? That sounds pretty important, especially after finding out the particulars of Dunkelzahn's death. Why was he concerned with the leaders of the Tir governments revealing their real identities? Who are they, and what is the reason for their animosity towards each other? Here's something that goes pretty much completely unanswered as far as I can tell: what is the 7 year plan Dunkelzahn leaves Nadja Daviar? How specific and extensive is it, anyway? How much did it shape the future of the game world? How much of what she does going forward is from him, and how much is her idea? How are you supposed to use any of the major corporate shakeups (Draco Foundation, Miles Lanier, Arthur Vogel, Nadja Daviar) from D's will without knowing where FASA was planning on going with them? What about the fact D used a human will instead of following dragon tradition? That seemed kind of important (as does the Jewel of Memory he leaves Lofwyr), but it was several years before the developers picked that up. And obviously, the most important...
WHO KILLED DUNKELZAHN?!Shadowrun has a long history of throwing a lot of plot threads out there and weaving some of them together over a long period of time...if they get expanded upon at all. So, I say again: use the EMPs in Cutting Black how you want and account for differences with future supplements as it happens, or wait for more explanation,
the same way it's always been. I just don't see why you think the EMP thing is somehow different from any of the others.