I got this idea while reading through Rival Magic. We all know that one of the key foundations of the Order's cohesiveness is the Parma Magica. Not only does it grant generalized magic resistance, but it incorporates a mechanism to block the effect of another Gifted magus' social penalty so that all these magi can stand to be around one another to talk.
I'm imagining a Blatantly Gifted Bonisagus taking the notion that Bonisagus didn't quite finish the job: the Parma Magica ritual needs to shield the caster's social penalty, rather than shielding the caster from other Gifted magi's social penalty. Putting aside the thematic consequences for the moment, what level of Original Research would this be?
On the one hand, it could be a Minor Breakthrough: the Parma Magica ritual already exists and this magus is only modifying an existing ability and extending its uses.
It could also be a Major Breakthrough, since it's stretching the limits of Magic Theory and the Parma Magica ritual without 'breaking' it, per se. "These sorts of Breakthroughs are often Hermetic Virtues that can be taught to the Gifted." (HoH:TL p. 26) One could argue that it is incorporating the Gentle Gift hermetic virtue as part of it, in this case. "Incorporating types of non-hermetic spell casting into Hermetic magic is another example of a Major Breakthrough;" (HoH:TL p. 26) I could even see a case where some hedge wizard faction has invented a ritual to shield their Gift's effects so that they can live among their mundane population in peace; a Bonisagus theoretician would certainly be interested in incorporating this into Hermetic Theory.
Given the game-changing effects, I could see an SG deciding it's a Hermetic Breakthrough -- the goal of an entire character's research over many decades. The Parma Magica ritual itself is the only such breakthrough in the entire Order's history which changed the nature wizards interacted with each other. This breakthrough would change the nature of wizards' interactions with mundanes.
So that's the question for you guys: What level of breakthrough would you say it is, and why?
Thematic Impacts
As mentioned above, this breakthrough would effectively give every magus a conditional Gentle Gift (conditioned on them having their Parma Magica up). This would allow all magi to have more harmonious relations with mundanes and take out a significant portion of the tension between wizards and mundanes. This would lessen House Jerbiton's impact (the source of many Gently Gifted magi) since the Gentle Gift is one of their key tools to dealing with mundanes. That said, I'd imagine most magi would still prefer to leave dealing with mundanes to someone else; it'd just be nice to not have them all run screaming away when walking into a new town.
Mechanically, this would probably reduce the Gentle Gift to a minor Virtue as most magi would have the Gentle Gift's effects most of the time anyway.