Pandemonica,
The issue is that high ground gives the ranged character advantage on their attacks and disadvantage on incoming attacks. It literally invalidates the use of spells at the cost of movement.
So instead of strategizing about what spells to use, the player just spends their movement. There are other positioning choices that could be made as well if the player wasn't over-incentivized to move all their ranged party members to high ground.
Literally the player is making less choices on positioning and less choices on spells.
Where should I put my wizard? The high ground. If higher ground didn't provide a net trade of 10 in combat, we could actually consider where to optimally place the wizard to dish out their spells. Sometimes the high ground puts Gale out of range to use his spells, and you can't undo that movement.
So after enough play throughs, you'll be constantly spamming magic missile and shatter so you don't have to deal with higher ground. What matters is getting an enemy to zero HP. Having to start combat with my wizard attacking with disadvantage all because an opponent or two is on higher ground is lame. (A foot higher).
I would like to play wizard with strategic positioning and being able to actually consider what spells are best for the situation. Not Shatter/Magic Missile or you're screwed.
