Captain America: The Winter Soldier. When Agents of S.H.I.E.L.D. launched back in 2013, Coulson and his team were part of a global organization with phenomenal resources. But it turned out Nick Fury's S.H.I.E.L.D. had been compromised by Hydra, and it all fell apart with shocking speed.
Phil Coulson's time as director of S.H.I.E.L.D. was largely spent attempting to pick up the pieces. Although Coulson was keen to reform S.H.I.E.L.D. with the same kind of global remit, he found himself constantly reacting to the latest threat. Worse still, the resurgent S.H.I.E.L.D. was initially hunted down by the authorities, and then framed for a number of incidents, first by Hydra and then by the Inhuman-powered Aida. Coulson never really had the opportunity to establish a well-structured, secure organisation, and then was forced to the directorship on to Mack. And he clearly made a wise choice.
Agents of S.H.I.E.L.D.'s season 6 premiere jumps forward a year and reveals that Mack has made great strides in rebuilding S.H.I.E.L.D. after the events of Captain America: The Winter Soldier. Mack's S.H.I.E.L.D. use destruction of the entire planet in an averted timeline. Mack has initially focused his efforts on improving S.H.I.E.L.D.'s tactics in the field, with Agent May recruiting additional muscle, and he's divided his agents into strike teams. He seems to have successfully negotiated an agreement with the world's governments that has allowed S.H.I.E.L.D. to step out of the shadows once again; notice that his teams are back to driving vehicles openly branded with the S.H.I.E.L.D. insignia. Now, he's moving on to the next stage of his plans; and that involves recruiting a new asset.
Mack's goal is to reestablish the S.H.I.E.L.D. Academy. He seems intent on demonic beings. Benson is clearly going to have a steep learning curve himself, especially with Fitz and Simmons offworld.
Although the S.H.I.E.L.D. team is still grieving their fallen leader, the reality is that Mack's skills seem to be far better suited to S.H.I.E.L.D.'s needs. He's grown into the role of director, and he seems to be much more of a skilled , allowing Agents of S.H.I.E.L.D. to rebuild at last.
Marvel's Agents of S.H.I.E.L.D. season 6 airs Fridays @ 8pm on ABC.