as the guy who cooks scenarios for my group the majority of the time, I too like the wiggle room.
I mean, I like deep, hard and accurate lore as much as the next guy, but that's a separate issue.
The old books that spelled out who was piloting what down to the last mech and infantry platoon leader? If you get a nitwit with, say, the Wolf's Dragoons book, I can imagine it might make it really hard to run turning points Misery or Death to Mercenaries.
Another one would be Day of Heroes and Turning Point: Glengary. Although at least I have both of those.