I'm sort of inclined to agree with ravenDivinity here, particularly the part about fooling the universe, that's... well. I know this is a liberal fantasy setting, but I feel as though Arcanism and Magus being a science makes this magus a little unfeasible. There's no science to taking another person's work. This is akin to answering a sum with the answer of another. The way magic works is based around an intimate understanding of its fundamental building blocks. Stealing another Arcanist's powers would mean needing to appropriate all of their skill-specific knowledge, too, otherwise the magus itself is useless.