I think I have said this quite a bit, but I think Highground Advantage would be better suited as +2/-2 instead of True Advantage, since it is taking the place of the now partially-defunct cover/half-cover system. That flat bonus still gives higher ground meaning, but also makes it balanced and gives other tactical decisions more meaning and weight when compared to just "move characters to highest position and attack.
Agreed ... personaly im all in for "alterning" high ground, so it make more ballanced game. But also totally against removal. :-/