During NPC phase creations, i had great pleasure to develop experimentation processes.
And with 8 maga rebuilding house Diedne in a (now certainly) alternative Mythic Europe, i had to notice that 2 of them were truly "labrats" which have, over one century of researches, improved the current magic theory in 4 ways, developing a new ability, which is the development of Magic theory: ADVANCED magic theory (lol, quite a false surprise ^^).
The Advanced magic theory ability is the new magic theory ability.
When a character learn it from a source (teacher, book) he starts with as much XP in it as he had in magic theory (basically, you add "advanced" before "magic theory" on your character sheet ). Any Magic theory or Advanced Magic theory knowledge can be used to improve your new ability. But due to difference between them, Magic theory source only provide half their normal value of XP.
This new magic theory gives access to 4 breakthroughs, and a few overcame limits :
1 you can now create quick charged item (it's charged item with 1 charge) in (magnitude of the charged item) hours, if your labtotal is equal or superior to the level of the charged item. This is the "quick charged item" minor virtue from HMRE integrated in MT.
2. you have access to new guidelines about fatigue (the same as in Energy magic, from HMRE), overcoming the limit of fatigue. You can then take fresh state of fatigue from other (ReCo as in core book, but not limited to "give" freshness to others), create freshness (but ritual if permanent), or destroy fatigue (long term fatigue is already canon, but short term (base 5) or preventing recoverying fatigue is new)
3. the (in my own eyes) most important improvement: spells need no more material arcane connection to be cast at "arcane" range. As far as you have a way to sense the target (knowing his name or look and localisation or identity is sufficient). The advanced magic theory is the way opened to wireless connections between magi who met at tribunals... and it's the beginning of a "wizard's war is not welcome" era.
With the new advanced magic theory, you can cast spell "at random places" even if no valid target seems to be there: example, you cast "PeCo" spell in front of you. If any invisible creature would be there, she would be affected even if you didn't know she was there and even if you just cast the spell "for fun".
4. (saga dependant : in our saga, parma can't be dispelled by PeVi because it's an hermetic breakthrough) you have access to a new guidelines [from the Imperitus Parma magica, another hermetic breakthrough] : "general PeVi : dispell parma magica if the spell base level +4 magnitudes is more than 5x parma. This spell must penetrate.
general PeVi: dispell aegis which level is less or equal than this spell base level +4 magnitudes is more than the level of the aegis. To permanently destroy an aegis, this spell must be ritual. it must penetrates the aegis"
With some spells as: "catapulta Imperita Parma magica : PeVi 30, voice, group: this spell dispells any parma less than (30+ stress die nobotche) /5 (round up) if it penetrates."; "Gladia Imperita Aegis, PeVi 25, voice, diam: this spell dispells an aegis which level is less than 30 during 2 minutes. It must penetrates."
And what about your Sagas? Have they been any "improvment" of magic theory which messed the Hermetic magic of the order?