Keep the circles. Give the mages more Autonomy.
-Make it law that all children attend the circle (just like they already do)
-Allow parents to visit their children at any time, Send them things and visitations with a Templar chaperon for a limited time.
-Circles train the children till they are of age, let's say...18
-Go through the harrowing. If the mage doesn't make it, tranquilize him like usual
-If the student makes it through the harrowing, allow the mage to live out in with the public with their families or on their own while their phylacteries are still within reach within the circle should they need to be tracked
-Also allow the option of the mage to stay within the circle for free to live as a tutor, teacher and other magical studies beneficial to thedas
-Allow noble mages to retain their status, however, he/she cannot be put into a place of authority (like king, queen, Viscount, etc) but can still remain nobles, prince and princesses. This is for their own good, to prevent any backlash from having a mage as a King or Viscount.
-Maintain a council of magi to discuss issues, new magics, chantry-mage relations, etc.
In this case. Less apostates because they'd realize they'd be living an oppression free life while learning how to control their magic. Happier mages because nobles get to stay noble and regular mages get to have families while being able to control their magic.
And the best part! NO BLOOD MAGIC. As we've seen from non-tevinter mages: Blood magic was always a last resort out of desperation. In this case, mages have no need to be desperate.