[Van Kada]

I'm going to be DMing Shadowrun for the first time in about 3 months time. I've played it a couple times before as a player and had alot of fun and I know an above average amount of the lore. But basically the idea for the overarching antagonist of my game was someone who wanted to wholesale destory the corpertate establishment by any means neccessery. I'd originally intended for this to be done by them making a Resonance infused super virus and deploying it in the Great Connection Resonance Realm inside the Matrix where it would spread to every net corner. Basically the thought being that 95% of the worlds economies are digital without the Matrix the megacorps would starve to death.
But then I heard about the CFD metaplot and how the corps genuinly fear the thought of mass public opinion shifting agaist them for fear an entire anti corperate movment would be born. With how powerful corperations are in Shadowrun that dosent sound like the kind of fear they'd have if it didint pose a genuine threat

Hope you guys could help me iron out the details. Thanks

[Shadowjack]

Considering there have been two major matrix crashes in history, this would absolutely be a colossal problem. Many corps would have backups of their data but setting up the matrix again, worldwide, would be a huge undertaking. A good villain would be a megacorp player with lots of holdings and underlings, who is also a friend of a superpowered A.I. The A.I would be completely secret and unveiled at a major point in the campaign.

[MercilessMing]

Something you need to consider is the risk that your players will decide that your Big Bad's plan is pretty good and decide to join them.  "Shaping public opinion against corporations" sounds like a nice plan.  A new Crash is a great campaign plot though.  I'd recommend following a story structure where first the big bad collects bits for the thing, then builds the thing, then tests the thing, then releases the weapon.

[Beta]

In Shadowrun the PCs are as apt to be working for the bid bad as stopping them ;-) (at least up until late into the process)

In one of the recent books it was stated that the current version of the wireless matrix was created a bit by accident, when evil experimenters made a network out of 100 technomancers.  It had useful features so they fed more computer power to it and grew it out to the grid we love to loathe now.  They eventually realized that those foundational technomancers had died, but the matrix carried on all the same.  Perhaps your big bad could be trying to take it down because they know this, and are somehow trying to avenge the technomancers? (or alternatively feel that it is inately corrupt because it was created by technomancers).  (I think it helps when the bad guy is not just trying to destroy things, but has a cause, no matter how crazy it is.)

[cantrip]

If you wanted to delve into the past, the idea that the Resonance has a copy of all data that has ever been in the Matrix is interesting. That would include data, viruses AIs...if someone is trying to find a copy of something from the past to release or use - things could get scary fast!