I am curious where you believe being AAA means its all group hugs and singing Kumbiya in the board rooms. A good chunk of the runs you will be hired for are internal matters, pitting one department against the other or sometimes a lower exec trying to make space above by outing a senior exec via runners. The Villiers are a good case of this as they may be in the same corp but they are not necessarily working to the same ends, as a few runs can show...
Horrors are not known for being subtle so most options for manipulations are lost on them, though a few do enjoy playing their games, but these tend to be the exception and not the rule. most are little more than beasts razing and scouring the land of all life, intelligent and otherwise.
Bug spirits, they are sneaky and manipulative. But considering the tales that a certain AAA is embracing using them as new tech, they don't need to manipulate a bunch of scattered A's and AA's, they are being brought in via the back door by a AAA itself. And it will bite them on the ares..err.. arse.

The various bean counters will be thinking they can negotiate with some of these things, because that's they have been bred to believe- everything has a price or can be negotiated and that they will sell out their own mothers and the rest of the world to secure that spot for themselves.
I am not saying that the level of organization that a AAA can bring to the table won't be useful in the coming fight. It will be, but under the current mindset most of the corps have now, I do not believe they will be any more likely to suddenly cooperate than a myriad of A's and AA's will be in the face of a common foe.
How do you improve that mindset? That would be the 64K nuyen question. Horizon's method is still just a bit too creepy, and these are the closest we have currently for anything approaching a 'nice' corp.