Yasuki Himiko wrote:I hate techniques that require an entire side bar to work properly in general.
Really, the Butei school has always been, on a conceptual level, problematic for that general reason. The persona is supposed to be something that doesn't break because "I Has Technique," but rather through legwork to hunt down clues as to the person's paperwork, family, origins, etc... along with the ability to verifiably knock holes in their grasp of their clan's nature. It's designed as a technique that isn't supposed to break or crack because of a conversation or two. It's supposed to crack after a suspicion is raised for secondary reasons and the person does extensive legwork to verify or puts the suspect under torture.
That is, effectively, a "Super Technique." It has always, in prior editions, 'trumped' a large number of other techniques (the amount of griping that used to fly from Kitsuki about older versions is exceptionally high). In this sense, it's one of the most powerful single courtier techniques in the game, as one can't simply bludgeon a victory out of it. It is something of an Ultimate Shield for spies, as it were, for which no Ultimate Sword exists in the game or has ever existed.
Basically, the tech's well balanced in 4e, but it's very existence will always be just as problematic in any given game as it always was. Either one permits Kitsuki lie detection to see through it, and thus its technique (which has no mechanical protection) is completely negated and no Butei can stand in the presence of a Kitsuki, or one must ultimately elect to grant it a lesser Ultimate Shield and innure the "Character" from casual scrutiny. The consistent selection has been to favor the butei and permit the Kitsuki or other investigator to just struggle through the old-fashioned legwork. If the Butei is a PC, a GM must prove to be clever to play out a specific suspicious NPC's playing out of that legwork, and go step by step over multiple sessions to chink away at the butei PC. That's particularly difficult for GMs, so they need to decide pre-game whether or not they want to deal with NPCs not seeing through this disguise generally (though individual lies are another matter). If the Butei is an NPC, it's much easier, and PCs can do the legwork as part of their adventure, but it may still be a headache.
Butei will always be a bugger-bear. They're difficult to permit in the average game because they are mechanically protected in ways other schools cannot be, and this level of protection is, in fact, somewhat necessary because of how the social mechanics work. But, yes, I definitely see how many GMs might decide "Why do I need a damned sidebar to run this class? No butei for you!" That's a reasonable response. Plenty of GMs did that before, back in older editions.