As a counterpoint to the forefoot space, the midfoot in the 4.0 Flyknit is quite snug. The laces in the shoe are flat too. This secure feeling in the midfoot felt good to me, but people with a wider midfoot may not care for this. Using lock laces may provide a bit of wiggle room, though I'm not sure how much.
Nike also touts a hexagonal outsole pattern on the 4.0 to provide more freedom of movement for the feet. With a six millimeter heel to toe offset, the Flyknit Free has a lower amount of cushioning than other shoes. In fact, for grins I decided to snap a picture of the 4.0 Flyknit in comparison to the Hoka Bondi B. Notice the drastic difference in the midsole when the two shoes are compared to one another.
When I first pulled the Flyknit Free out of the shoe box, I noticed that Nike included a sticker on the inside part of the shoe box that describes the uniqueness of this complex model. The picture above contains the caption in English on the left side. If you are intrigued with the Free and are already running in shoes like the Brooks Pure Flow, Pure Cadence, or Pure Connect, the Saucony Kinvara or Virrata, or the Pearl Izumi N0, N1, or N2, I would anticipate the transition into the Free to be relatively seamless. If the Flyknit Free is an option you are considering for the first time, I suggest heeding the caption on the shoe box: "Nike encourages you to get used to them gradually for a safer, more effective and more enjoyable experience."
On the web: Nike Free 4.0 Flyknit