To be clear, so nobody is disappointed:
"Secret" has nothing to do with "important."
I called
Dungeon Fantasy Companion 2 "secret" because I'm allowed to say I'm writing stuff but not
what I'm writing until there has been an official announcement. This is true whether I'm writing text for a free bookmark, a 12-page PDF, a 64-page softback, or an entire new RPG.
As these things go, I think
Dungeon Fantasy Companion 2 is something just about all
Dungeon Fantasy Roleplaying Game players will want, but not something wildly unexpected that takes the game off in some crazy new direction.