I think Fitz will play a big role in season 2. My theory for his character is he has sustained brain damage which will leave him with memory loss and forgetting his feelings towards Simmons, as well as his loyalty to shield, part of the show will be exploring this through season 2 as a side story to the main theme.
-Nick Fury had told Simmons that he sustained brain damage if memory serves correct
-It would continue the arc of the Fitz/Simmons relationships, will they, won't they, very popular for TV shows to do and causes the audience to invest in their characters and care more, whether negative or positive. I don't think they would give this up after 1 season. It would also create a possible interesting arc with Simmons, Fitz, and Triplett, potentially testing his loyalty to his team and shield.
-Would be interesting to explore his loyalty to shield without the memories to back it up as to why, and in the end his loyalty is proven, perhaps in some sort of sacrifice where he gains powers for season 3
I know a lot of this is reaching, but I think it would be an interesting way to deal with the character of fitz and give us a new look at him at the same time.