Gwen becoming Queen scene is part of the dream/vision that torments Morganna, person high up in Morganna's court who becomes concerned about her behaviour is Geoffrey of Monmouth, I dont think Uther dies this season and he will reward Gwen in apology to Arthur for all the trouble he puts him through and make her nobility in order to create her as suitable for Arthur...Morganna will claim she was enchanted by Morgause to make her do what she did, so she wont be killed or banished, but she will be married off to Cenred or some one to take her a safe distance from Camelot because she sure cant stay there after all this!