thanks everyone for the explanation. however, I did not mean the height advantage. "Table" or "stone". Roof, rafters, rock - that's what "serious" height I'm talking about. I would like to keep this advantage, but the idea of obstacles and penalties is a good idea. I love to play rooftop sniper. but it also seems strange to me that the enemy does not try to leave the open space. when he doesn't understand where they are shooting from
Keep in mind even if High Ground doesn't apply Advantage to the attack, being out of sight still does. The player can use the hide command and get Sneak Attack with Astarion (From the rafters, etc.)
If High Ground (2d20) Advantage is removed from the game, the player now has a meaningful choice on how to use their bonus action. While currently in game, there is less strategizing once you see you have Advantage from High Ground in the HUD.