User blog comment:MerlinNimueh/Series 5: confirmed facts/@comment-4650675-20111220195713

Indeed, Morgana will definitely be there, and she will still be the main villainess, along with another, familiar villain from the past (most likely Mordred) and it will be a major storyline in series 5. Also, Gwen and Arthur are said to get married in 4x13, so I guess Gwen being queen will also be an important plotline of Series 5.