I love the idea of Arcane, it just needed to be play tested MUCH more than it was.
It added flavor of a raw, unwieldy, extremely powerful source for magic. The risk was sometimes NOT worth the reward lol
I would also caution you about "scope creep". Talent law (lord help us) did this. It was the WORST. Players started off sometimes at level 1 but the equiv of a level 10 or 15.
I have an 18 page homebrew book of "restrictions" that inhibits, pulls back, restricts and modifies the entire Talent and Flaw book to be more balanced and playable. I did the same with the "Arcane Companion" however it didnt need NEARLY as much work to balance.
A good rule of thumb, if you introduce something, and after a while ALL players adopt it and stop playing or diverging from it, it is a problem.
Example: ALL fighters chose "Blessed by a war god" and all casters chose "Eloquence" and "Power" after about a year of introducing Talent Law to my group. I wont go into detail about these monstrosities but suffice to say, they are restricted now.
Hope this helps!!