Poorly Executed Flashbacks
The show's prodigious flashbacks should've opened a window into who Danny Rand is by contrasting his contemporary actions and behavior with those of his past. Instead, they mostly subjected viewers to scenes of the plane crash that killed Danny's parents, played on a loop. Presumably, those were intended to drive home the childhood trauma that helped to shape who he is today. However, we can only watch Danny's mother sucked out of the plane's cabin so many times before the event reaches a comical pitch.
Rather than scenes of the crash, followed by repeated flashes of the discovery of 10-year-old Danny by monks from K'un-Lun and his strict training, both the viewers and the character would've been far better served by more fully realized, and better-positioned, scenes of an unhappy orphan seeking to leave the mystical city at every opportunity, only to find the gate closed. Maybe then we could understand why, as an adult, he chose to abandon the position he risked so much to attain.
Similarly, viewers might've been provided with a clearer picture of K'un-Lun, better establishing it as the multicultural society Marvel Television so obviously intended, while dropping hints to the ancient city's nature and purpose, as well as its war with the Hand. So, too, would such flashbacks illuminate the obviously complicated relationship between Danny and Davos, the former best friend turned rival who wasn't introduced until the ninth episode, leaving the audience to flesh out much of the backstory themselves. (Their dynamic becomes far more nuanced if you imagine that Davos isn't merely resentful of Danny's position as the Iron Fist, and angry about his decision to turn his back on K'un-Lun, but also in love with him.)
Does The Defenders change any of that? Not really. Although Danny experiences a nightmare vision in the first episode, which is either fueled by guilt from abandoning K'un-Lun or a glimpse of what's to come, the first half of The Defenders devotes its sole flashback to Alexandra, the leader of the Hand portrayed by Sigourney Weaver, and Elektra. Thankfully, we're not forced to watch poor Rands die again.