Obviously we can't change anything now but if looked at in the proper perspective at the time of it's release, the reliable/proven titanium horizontal shutters - pioneered by the F then the F2, was the choice in design for all the PRO interchangeable viewfinder cameras of the time. It won't burn even if mirror is locked up and pointing to the sun. Probably due to NASA requirements at the time? In the EOS 1VHS manual there is a caution stating, "During mirror lockup, do not point the camera lens at the sun. The sunís heat can scorch and damage the shutter curtains."

Interestingly enough the oldest design - XK released in 1972, had the fastest sync speed of the group.
  1. XK 1/100
  2. F-1 1/90
  3. F3 1/80
  4. F2 1/80
  5. LX 1/75
  6. F 1/60

You'll notice that Nikon didn't even raise the sync speed from the F2 to F3 release.