That suggests player character magi treat the Code as actual laws and not a suggestion (maybe it’s just my troupe that is like that?), and mundane characters don’t worry about the legal consequences of their actions. By removing spontaneous spells (or ingenious re-use of existing formualaic spells), I would feel that narrowed some of the options and would force players into using social skills or inventing a solution.
I believe CJ started Thirty Tribunal Cases and made it as far as sixteen. Yes, that’s certainly a good idea and worth having another go fourteen years on.
Let me digress into Ars Magica history here - there was a point at which Atlas Games was considering making a spin-off of Ars Magica based on Gumshoe, which had the nickname “Magic Shoe” among developers. The premise was that you would be Quaesitors investigating magical cases, and you would use Gumshoe-derived mechanics to handle the investigation. As it was never published, I have no idea if it would have worked, but I’m sure Guernicus- based adventures (or a saga) could work well.