So essentially: Free Advantage based on nothing more than positioning is a massive advantage on par or better than the most powerful magical weapons in the setting?
nothing more than positioning????
You joking right? positioning is key in any fight. It's huge in any combat even vs highly advanced forces and numbers... in any combat it's huge you sir have zero clue on tactics and strategy.
of course positioning is important, particularly in a fight like we see in dnd. It gives you much better sightlines, it restricts the sightlines enemies have on you, it makes it much more difficult for them to get to you, and you can use it to force attention onto particular party members when needed.
All of these things are either already implemented, or are absolutely something you can make work in a game like this. Good positioning is incredibly powerful without it giving you the effect of one of the strongest magical spells available to non-divine casters. A party at second level getting the effects of a 9th level spell from expending their movement and maybe bonus action for a turn or two (if that) is not a reasonable change to the rules.
Imagine if we got meteor swarm for free just for standing near a bonfire? Or power word kill for passing a DC5 persuasion check?
