What if when Odin ordered Frigga out of the room when her son was at his trial after the events of "The Avengers", Frigga refused to leave. She demanded to be at Loki's side.
After Malekith's attack on asgard, he is found and killed swiftly. Frigga is still dead, and Loki still imprisoned. They found a way to get the aether out of Jane and all is well. The avengers come to Asgard for a 5-year celebration of the battle of New York, when the topic of Loki comes up....