So, there is a small thing I have wondered about as one of my players has had the idea of pursuing it: That player suggested that since it was possible to cast a spell with all forms as requisites, that with a breakthrough, he'd be able to cast a spell with only the technique alone. I have for now let him decide to work on it on the mere fact that even if it was impossible, the magus wouldn't wholly know that unless he worked on it in the first place.
Now, that brought up the question of what casting a spell with all forms as requisites even does, and how Pure Technique Spells may improve that. I assume out the trickiest case to understand is Creo, since Rego, Perdo and Intellego are easy to stretch over and since Muto will cause unnatural things disregarding of it's true nature anyways. There are likely two cases to be checked here, I guess: A Creo spell with all Forms as requisites may be used to repair, or to create, certainly using Vis during it.
If I see it correctly, RAW would interpret these two cases when using a spell with all forms as requisites(As in, it uses all requisites at all time, not just changed requisites when casting individually):
The Repair spell could repair anything at the target, with the base size of about a human, with the ability to repair more and more difficult things at the target with higher levels. Most spells would have a high base since to repair most things you need a high base level. Also, a Boundary Spell with all Form Requisites may attempt to fix everything in the designated area of fitting size, strengthening fires, filling seas, healing plants, animals, bodies and minds, while illusions are restored and objects are repaired to their original design. Again, such a spell would be very, very hard to learn anyways since a high base would be necessary.
The Create spell would fail. The magus would try to create something most akin described to the essence of creation (probably enraging God in the process), but since the magus has likely never seen the essence of creation, or sensed it in any ways, he won't be able to create a thing he doesn't know exists for certain. Alternatively, he could simply create a wild, unstable mess of all forms, contained in a single area, though that creation would probably look purely demonic, what with the fire turning water into steam, the air raging around inside it, the emotional feeling exuded from the object and the strange, uncontrolled sounds or looks of the sphere, which is massive and likely very noticable by magic. The only use of creating such a spell would likely be to demonstrate something as a magus, or to completely baffle mages using the Sight of the active Magics by overloading their senses, although a Vim spell alone may be better for that.
Now, what could make the turning of spells into Pure Technique Spells better, as you'd lose your lowest Form Score in exchange for that? I'd assume that scrapping all the requisites would lower the level a bit, as there would be no more requisites which would influence the level. Then, it might not fit nicely into hermetic theory enough to be as detectable as other spells. I can't think of any other useful cases for it right now.
What else is to be noted? For now, it seems harmless enough to not break the game too harshly, and I don't wholly know what the limits of it would be (and what that might cause). Am I overlooking something that may make it more powerful or even strong enough to prohibit it entirely?