Season 4 has split it's 22 episodes into 3 story arcs, with one key link. The season also ties in loosely with the release of Doctor Strange, adding mysticism to the MCU.
The first arc, featuring the Ghost Rider, was widely praised for bringing the show back on track after a fairly bleak end to season 3. Personally, I felt that these episodes relied too much on the Ghost Rider and his family and I didn't feel any particular attachment to them. Robbie Reyes (Ghost Rider) didn't feel like a good fit for the team, so it was obvious that he wouldn't be sticking around for the long haul.