With Kevin Feige saying that Thor: Ragnarok impacts heavily on the movies that will come after it, it seems feasible that the main bad guy who is set to terrorise the Avengers, the Guardians of the Galaxy and indeed the entire universe will be making appearance. Remember how The Other said to Loki in the Avengers movie that, if he failed in his plans to take over the Earth, Thanos would make him "long for something as sweet as pain?" Have you noticed that hasn't happened yet? Strange, huh? Well, the likely explanation is that Loki saved his own skin by bargaining with Thanos - and expect that bargaining to come light in Thor: Ragnarok. It will come to light that Loki either handed Odin over to Thanos prior to him posing as the Allfather in order to sit on the throne of Asgard, or will play a major part in giving Thanos access to Odin's trophy room, where the Mad Titan will get his hands on both the Tesserect and the actual Infinity Gauntlet - both of which are currently stored there. Perhaps the bargaining will actually have involved giving Thanos both Odin and said access to the trophy room. Either way, you can definitely expect the pair to still be in cahoots come the time of this movie.
