Sigh ... Sometimes i have the feeling that i unconsciously speak Swahili ...
Let me ask a little simplier then: Is part of your suggestion to implement any other mechanic to make your character safer as you claim ... or are you make common asumption that you will be safer, just bcs of your location ... and therefore ignoring litteraly everything enemies could theoreticaly do to turn high ground against you?
What other mechanics would need to be added? In some higher elevated positions there's only one of a few ways to reach the ranged characters. I haven't played since like patch 2 or 3, but even now I can think of several such locations.
In the Goblin camp exterior there's a ladder to a high elevation where basically everyone was hostile and IIRC the only way to reach it was the very tall ladder. Positioning ranged up there was basically a guaranteed win because they would all have to rush the ladder where they'd be subsequently pushed off and killed off by arrows or spells. Outside the cave is a similar situation. They need to climb the cliff face or flank around, either way an area control spell blocks the area while ranged kills them off. The first battle after getting off the ship with the Intellect Devourers forces them to climb the side where melee pushes them off and ranged picks them off. Same thing for when the Grove is attacked initially.
You don't need any other advantage than that and nothing mechanically would be needed. I have no idea what you're asking for beyond that. It's an instant win without the advantage/disadvantage in many cases.
