In the comics, Superman actually went through sort of a half identity crisis/half spiritual reawakening when he realized that he was mortal...
As much as I love Tom Hiddleston, I think it would be fun in ten years or so to have Kid Loki and the Young Avengers...that's such an awesome comic!
Also, Joss Whedon said once that he felt that Tom Hiddleston would win an Oscar by the time he's 40 and I agree with him...at the very least, he'll be nominated because he does balance out his Marvel roles with smaller stuff, even short films.
However, I feel his best role on screen was Hal in Henry IV, Henry the V, part 1 and Henry the V, part 2. He was amazing there.
I hope we're able to have even more of his range as Loki in Thor 2...I did notice that his delivery of the line, "When do we start?" was unlike any of Loki's dialogue before.