User blog comment:The big croc/straw hats haki/@comment-2229670-20101214201403

There aren't so many Logia Devil Fruit users, so I don't see a reason for others than Luffy to have Haki. Or if by any chance there will be two logia opponents at the same time, one of them will have a weaknes that does not requiere HAKI.

Maybe they will develop haki later, but this will be in the next arc. Not this that just started.