Greetings Maester Attewell. If the Riverlands had a strong local monarchy ruling it (and having done so for quite some time), would you advise the king to exile either the Brackens or Blacwoods, similar to what happened between the Manderlys and Peakes in the Reach? Thank You!

I would see the exile of the Manderlys as an example of weakness on the part of Perceon III Gardener, who in the attempt to rid himself of the over-mighty Manderlys allowed the Peakes to become over-mighty.  

Successful monarchs, like Gwayne III Gardener or the Starks dealing with the hill clans, extend their own power by making feuding clans turn to them as arbitrators, while using their own military power to keep the conflict from going hot.