1) Perception is necessary for Magic.
If i want to send out a fireball, i need my perception to both cast it to begin with and after casting it to have it cast in the right location. This means intelligence does not determine a DC, but rather Perception does if you are using the DC system. This immediately fixes the classic problem of quad wizard and linear fighter to some extent.
i like this idea,, would help prevent mages from having single stat amd make perception slightly more useful for 1 build, th ough id still like to see perception with a few more benefis