I hope they don't go any of those routes, no offense. They all seem a bit too complicated for this show or really the marvel universe they are currently portraying to actually pull off.
Really any storyline they do from this point that i can think of will at best annoy me for a few episodes then whenever they get back to their normal routine I think the show's steam for me will pick back up.
They started mostly as a sort of different procedural, and then now started to move into each episode is part of a larger story type of deal instead of a few minutes out each episode being used as the vehicle for that. Either can work, but I don't think they should try to stick with both.