Yes, a fighter who makes a ranged attack could mark a target at range. However, the big advantage of marking is that you can take a free shot at the marked target if they attack someone else or try to move. Unfortunately, you are limited to melee attacks for this, so if you mark them way off all you'll can is a minus two to hit against one of your fellows assuming they marked target can't attack back at range.
Here's the updated text:
Page 76: In the second paragraph, replace “a marked enemy that is adjacent to you shifts or makes an attack” with “an enemy marked by you is adjacent to you and shifts or makes an attack.”
In addition, whenever an enemy marked by you is adjacent to you and shifts or makes an attack that does not include you, you can make a melee basic
attack against that enemy as an immediate interrupt.
It has been suggested that a fighter can mark more than one target if he uses a power that targets more than one. There aren't that many fighter powers that allow for multiple targets, but there are a few.
There are some questionable tactics for Paladins where you mark a target 5 squares away, chunk a javelin at it and then move even further away forcing them to either find a way to attack you, possibly drawing attacks of opportunity moving past your companions to get at you or not attack or take automatic damage from attacking someone else. Such cowardly tactics would not be appropriate for most Paladins, but with the removal of alignment restrictions, Paladins of non-good deities might well do such a thing. I can see using it against a foe that is almost impossible to hit. But the three plus Charisma mod damage and a basic ranged attack doesn't really seem as valuable as what a Paladin can typically do by just stepping and using an at-will power.
I would guess the Sword Mage is the one best suited to take advantage of the ranged mark.