Gene Editing as far as helping diseased and suffering humans is good.
But the basic problem is rich and affordable couple in future will think that by using this technology they would like to have their children as bright as Abraham Lincoln or like these:

then what happens?
like wise a hard core terrorist wants to have a hardest core? then what happens?
if the technology can be controlled up to helping sufferers that would be fantastic. but who can monitor and control?
parallel GOD or Satan is dangerous.