Well, your argument was that they should make it melee only, which is unfair for ranged, because it is currently unfair for melee. That statement is flawed in itself for obvious reasons, it should be fair for both.

Sure, ranged can proc it more. Even twice as much more. Say a ranged champ procs it 50 times, which is 4 minutes with flawless timing every attack, so lets say that takes 8 minutes of both laning and out of lane time, a more realistic number. This will be 10 minutes of game time as purple team wont arrive to lane until 2:00 due to leashing jungle.

That is 150 gold, from 50 procs, in 10 minutes. For a melee, with 50% of that, they earn 125 gold from 25 procs. By 20 minutes of laning there is a 50 gold difference. AFter that laning ends, but of course ranged still kite and poke teams easier, but in fights melee will survive longer. So lets say after 20 minutes melees only hit 1/3 of the time that ranged do.

Ranged get 300 gold in 20 minutes, melee 250.

The next 20 minutes, ranged get another 300 and melee get 166.

So, by this random maths, ranged earn ~175 more gold than melee. Thats the cost of 1 health regeneration per second at 40 minutes into the game.

Therefore:

It does not make a difference between the two as it is so minimal.

It really does not matter.

As someone who plays Taric support a fair amount, I can honestly say I am fine with getting 2 less vision wards than a ranged support over a 40 minute game, as I will have 4x their defensive power, and more offensive power half the time.

tl;dr: It doesnt need changes because it is so trivial a difference.