my 2 cents on rumor mill:
When 3x jackson was in, you just had to know that RM was out there and expect it. This was not great for deck diversity-- not only did it hose the defensive upgrades that made scoring glacier decks like foodcoats work, but it also screwed over decks that happened to have an innocent bystander in an important role (like Mark Yale in Titan decks, Batty in rigshooter decks, etc).
While RM was banned, it was good for corp diversity because “innocent bystanders” were safe to build around (or at least make an important part of your game plan).
Now that RM is un-banned, I expect to play a lot more corp games where I randomly get hosed by it, even if its main target is Moons + Stinson and they aren’t in my deck. So, it remains to be seen what impact it has on corp diversity. I think that best case scenario, it either (a) encourages corps to add another current or 2/1 to help clear it in a pinch or (b) encourages corps to play decks that don’t necessarily rely on the main RM targets to win. It’s also possible that the existence of RM pushes players back to horizontal games, which (moons aside) don’t rely on unique cards as much as vertical strategies.
RM’s existence introduces a dependency between the power level and popularity of every unique asset/upgrade that gets printed, which seems like a nightmare to manage. It raises the risk of a long inter-MWL stretch where RM sets up a lot of frustrated corp players and a narrow range of viable corp strategies.
That all being said, Boggs and the playtesters did great with the last MWL and the current cycle, so I’m giving them the benefit of the doubt for now.