Based on both my own experience and a recent conversation with five other tentpole directors, the most common challenge/difficulty for event-movie filmmakers is getting unwanted major script changes late in pre-production.

— N O S ⋊ Ɔ I ᴚ ᴚ Ǝ ᗡ ⊥ ⊥ O Ɔ S (@scottderrickson) September 10, 2019