they buff all of the range/melee weapons because they nerf weaponbased damage on almost every ability.
weapondamage almost doubled as a rule of the thumb, atleast for 85s weapons, dont know if it is accurate for 70 weapons
and they dont have to buff hunter weapons because they lose melee weapons, they remove wands/relics/sigils, too. its easier to "balance".
gurthalak maxdmg has been almost exactly doubled (same for vishanka and pretty much every weapon ive seen so far), so the "no melee weapons" isnt really an argument, they think its easier to balance with lower %weapondamage on abilities but higher weapondamage on the weapon itself.
/edit:
as i see it now, it seems like they didnt buff the 70s weapons as big as they did to 85s weapons, maybe, if iam not wrong, this will lower overall damage (what can you tell about it lovestotwink?), but maybe they set the %weapondmgratios on the abilities higher.