There will be Wizards

How can one have a fantasy story without wizards? Furthermore, who is to say the Hushers are the only ones with the Secrets?

First, as individual dabblers they would be crushed. But then again, if people didn't allow any secrets out, then the Hushers wouldn't last that long. The key I think is that the Hushers would focus on anything that had large or kingdom changing application. After all, politics is what they're really interested in, which among other things means the technology of the Abysmali and the Enchantments that Simsaur magic can create.

Of course, magic is largely a matter of making arrangements with the right things or utilizing existing agreements. Rocks and the like tend to have much longer memories than most after all. On the other hand, one of the reason I have been so careful to outline various kinds of magic is the fact that I want my magic to be just that, magic. So while I have underlined the actual functional rules behind it, the reader shall be privy only to the surface. Still again, the point is that a true wizard in the Fantasy sense collects these secrets as a hermit might, one bit at a time.

That means some of the names of summoning the Ma-Ka-Fa, the names of some Gods which can be sommoned or dealt with. There would be some of the nature of prophesy taught, but Dreams and Destiny would be more a wizard's creed since Prophesy is the matter of Kings and Empires.

Thus with the Hushers there is a reason for Wizards to act like wizards, lonely and seculed, occasionally dabbling in the affairs of men, but only the most stunningly powerful. Hedge wizards or witches could provide basic services so long as they do not become too uppity or break the Laws as the Hushers have set in the reserving of knowledge to themselves.